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Dissertations / Theses on the topic 'Ship resistance'
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1
Sen, Sharma Pradeep Kumar. "Sensitivity analysis of ship longitudinal strength." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/45183.
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The present work addresses the usefulness of a simple and efficient computer program (ULTSTR) for a sensitivity analysis of ship longitudinal strength, where this program was originally developed for calculating the collapse moment. Since the program is efficient it can be used to obtain ultimate strength variability for various values of parameters which affects the longitudinal strength, viz., yield. stress, Young's modulus, thickness, initial imperfections, breadth, depth, etc.
The results obtained with this approach are in good agreement with those obtained by use of a more complex nonlinear finite element program USAS, developed by American Bureau of Shipping.Master of Science
2
Voxakis, Petros. "Ship hull resistance calculations using CFD methods." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/74895.
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Thesis (Nav. E. and S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 77-78).
In past years, the computational power and run-time required by Computational Fluid Dynamics (CFD) codes restricted their use in ship design space exploration. Increases in computational power available to designers, in addition to more efficient codes, have made CFD a valuable tool for early stage ship design and trade studies. In this work an existing physical model (DTMB #5415, similar to the US Navy DDG-51 combatant) was replicated in STAR-CCM+, initially without appendages, then with the addition of the appendages. Towed resistance was calculated at various speeds. The bare hull model was unconstrained in heave and pitch, thus allowing the simulation to achieve steady dynamic attitude for each speed run. The effect of dynamic attitude on the resistance is considered to be significant and requires accurate prediction. The results were validated by comparison to available data from tow tank tests of the physical model. The results demonstrate the accuracy of the CFD package and the potential for increasing the use of CFD as an effective tool in design space exploration. This will significantly reduce the time and cost of studies that previously depended solely on physical model testing during preliminary ship design efforts.
by Petros Voxakis.
Nav.E.and S.M.
3
Thorsen, Ingvill Bryn. "Estimation and Computation of Ice-Resistance for Ship Hulls." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18757.
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The oil price continues to increase while oil companies search for oil in new areas. There is assumed that 25% of the world’s hydrocarbons are located in the arctic area. Operating in these areas will be a huge challenge due to extreme low temperatures and ice condition Today one can predict with good accuracy how a ship will manage in different ice condition. Research on ship operating in ice the last decades has resulted in many different formulas for predicting ice resistance on a ship hull. Analytical and numerical methods are developed to estimate the resistance working on the ship hull under different ice conditions. Model test will still be the most accurate prediction, but the other methods may give you some guidelines on what to expect. This thesis contain a theoretically study of ice physics and mechanics. The formation and development of sea ice has been reviewed. The Ice Load Monitoring system tested on the Norwegian coast guard vessel KV Svalbard is described. Three different analytical ice resistance calculation methods are described. The three methods are Lindqvist (1989), Keinonen et al. (1996) and Riska et al. (1997). Data obtained from the Ice Load Monitoring system are used to estimate the full scale ice resistance on KV Svalbard. The three analytical methods are calculated with KV Svalbard as a reference ship to be able to compare with the full scale measurements. MATLAB is used for the calculations.
4
Peng, Hongxuan. "Numerical computation of multi-hull ship resistance and motion." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ63482.pdf.
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Johnson, Brian (Brian David). "Resistance and wake prediction for early stage ship design." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/85527.
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Thesis: S.M. in Naval Architecture and Marine Engineering, Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 75-76).
Before the detailed design of a new vessel a designer would like to explore the design space to identify an appropriate starting point for the concept design. The base design needs to be done at the preliminary design level with codes that execute fast to completely explore the design space. The intent of this thesis is to produce a preliminary design tool that will allow the designer to predict the total resistance and propeller wake for use in an optimization program, having total propulsive efficiency as an objective function. There exist design tools to predict the total resistance and propeller wake, but none that provide adequate computational times for the preliminary design stage. The tool developed uses a potential flow solution coupled with an integral boundary layer solver to predict the viscous resistance and propeller wake. The wave drag is calculated using a modified linear theory, thus eliminating the need to run fully three-dimensional free surface CFD codes. The tool developed is validated against published Series 60 test data.
by Brian Johnson.
S.M. in Naval Architecture and Marine Engineering
6
Petersson, Emil. "Study of semi-empirical methods for ship resistance calculations." Thesis, Uppsala universitet, Tillämpad mekanik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-413700.
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In the early ship design process a quick overview of which shipdesign that could be the optimal choice for the intended usage needsto be investigated. Therefore the feasibility and accuracy ofinterpolating between measurement data from model resistance serieswhen estimating unknown hulls were conducted. A parametric study wasundertaken in order to investigate which parameters carry the mostimportance in regard to calm water resistance for semi-displacinghulls. In order to asses the whole estimation process one semidisplacing ship (FDS-5) and one bulk carrier with a bulbous bow (JBC)were estimated in regard to calm water resistance by using semiempirical methods and were later compared with CFD results. The CFDresults came from a in part parallel conducted work. The resultsshowed that it is possible to estimate the total resistance withsemi-empirical methods to an unknown hull by linear interpolationwith an accuracy of below 5% in the designed speed interval both forFDS-5 and JBC. The CFD simulations achieved a lower accuracy comparedto the semi-empirical approach, however by furhter calibrating themodels, the accuracy could potentially be improved. Linearinterpolation between two hulls in order to estimate an unknown hull,is only advised when the hulls are nearly identical. Meaning that thehulls must be of the same ship type and that only one parameter isallowed to differ compared to the unknown hull. The parametric studyresulted in parameter importance in falling order: Slenderness ratio,length-beam ratio, longitudinal prismatic coefficient, blockcoefficient and beam-draught ratio. Even though the CFD approach notyet is completely reliable, it could still be a useful complement tothe semi-empirical approach by calculating parameters such as adynamic wetted surface, resistance due to appendages or airresistance of the full-scale ship. Simply by incrementally increasingthe accuracy of individual resistance components an overallimprovement could potentially be achieved.
7
Cooke, Robert. "An experimental investigation into the components of ship resistance." Master's thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/15823.
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Includes bibliography.This thesis is an experimental investigation into the components of ship resistance. The traditional Froude method of scaling is investigated with reference to the measurement of skin friction and viscous pressure resistance. A literature review is given on the theoretical background and experimental measurement techniques. Two models are used for the experimental work, which sizes are in the geometric ratio of 2,7 to 1. The model form is half a body of revolution with a vertical sided superstructure. The block coefficient of the model is 0,621 and the length to beam ratio is 7. Two surface models and one reflex model are tested. One of the models has 40 pressure tappings located on its hull which are used to measure the total pressure resistance of the model. The components of resistance directly measured are total resistance, total viscous resistance and total pressure resistance. The resistance components inferred are skin friction resistance and wave-making resistance. The deduced skin friction is found to deviate from the Prandtl-von Karman skin friction formulation. The wave-making resistance agrees favourably with the predicted values using Mitchell's integral. The total viscous resistance increases sharply at Reynolds numbers greater than 3 x 10⁶.
8
Xu, Jinsong. "Estimation of wave-induced ship hull bending moment from ship motion measurements." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0029/NQ62460.pdf.
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Utama, I. Ketut Aria Pria. "Investigation of the viscous resistance components of catamaran forms." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297613.
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Tregde, Vidar. "Aspects of ship design: optimization of aft hull with inverse geometry design." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-134.
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The main contribution of this thesis is on the study of optimization methods in aft hull design. The optimization methods are inverse geometry design methods to find an aft hull with the flow velocities we specify. The analytic foundation for the flow is given by Stratford in [31], and gives a prescribed velocity distribution on the aft body. With the parameter β we have adjusted this flow to have a certain margin to separation along the pressure recovery region.
This principle and optimization method are successfully applied to design of ships with pram-type aft hull. The 2D optimized profiles corresponds to centerline buttock, and 3D hull sections are extended from this centerline buttock with a bilge radius.
Stratfords original pressure distribution for pressure recovery region were meant for Reynolds numbers up to 107. We have extended Stratfords formula to yield for ship full scale Reynolds numbers to 109.
Different optimization methods were programmed and tested. The best routine for our optimization of aft hull with Stratford flow, was when the offset y-value were the optimization parameter to be changed. When we tried to optimize a complete 2D profile with a given pressure distribution, it worked best to use the variables in a B-spline as the optimization parameter.
Extensive windtunnel tests and towing tank tests are carried out. The tests verified the hydrodynamic properties of the hulls.
Towing tests indicates that the optimized hull lines have lower total resistance than conventional ships with the same main dimensions. Both the frictional, viscous pressure resistance and wave making resistance are significantly lower. Further we can increase cargo capacity with the same power consumption, and achieve a more favourable distribution of the displacement in the aft hull.
This study has shown us that the slant angle for the bottom of the aft hull should not excess 15º with horizontal plane due to danger of separation over the bilge, and longitudinal vortices forming.
11
Chun, Ho Hwan. "Theoretical and experimental studies on the resistance of SWATH ships." Thesis, University of Glasgow, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237814.
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Antunes, Filipa Alexandra Paiva. "Ship transport of marine invasive species and its stress resistance." Master's thesis, Universidade de Évora, 2014. http://hdl.handle.net/10174/12339.
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In the context of biological invasions, ship transport plays an important role in the transference of species around the world. During this process organisms are exposed to several stressful conditions, which do not prevent them to arrive in areas where they did not occur before. The marine invertebrates Carcinus maenas and Mytilus galloprovincialis natives in Portugal, have already established stable invasive populations in several regions worldwide. This study exposed organisms of both species to stress conditions similar to what occurs in ballast tanks and on ship hulls. Results showed a high survival of pre-stressed Mytilus galloprovincialis individuals when compared to non pre-stressed organisms when exposed to air exposure, hyposalinity and heat events. However when Carcinus maenas was exposed to heat stress, there was no significant difference between groups with a different stress history. These findings suggest that transport on ships is not only a vector of dispersal but also a vector capable to increase the resistance to stress conditions in potential species invaders by selection of resistant individual; Resumo:
"Transporte marítimo de espécies marinhas invasoras e sua resistência ao stress"
No contexto das invasões biológicas, o transporte marítimo desempenha um papel importante contribuindo para a transferência de espécies em todo o mundo. Durante este processo os organismos são expostos a variadas condições de stress que não os impede de chegar a áreas onde não ocorriam anteriormente. Os invertebrados marinhos Carcinus maenas e Mytilus galloprovincialis nativos em Portugal, já estabeleceram populações invasoras estáveis em várias regiões do mundo. Neste estudo, submeteram-se organismos de Carcinus maenas e Mytilus galloprovincialis a condições de stress semelhante ao que ocorre em tanques de água de lastro e em cascos de navios. Os resultados mostram uma maior sobrevivência dos indivíduos Mytilus galloprovincialis pré – expostos a condições de stress quando comparado com organismos sem uma prévia exposição a esses eventos de stress, quando expostos ao ar, baixa salinidade e altas temperaturas. No entanto, quando Carcinus maenas foi exposto a temperaturas mais altas, não houve diferença significativa entre os grupos com diferentes exposições ao stress aplicado. Estes resultados sugerem que o transporte marítimo não é apenas um vetor de dispersão mas também um vector capaz de aumentar a resistência a condições de stress em potenciais espécies invasoras, nomeadamente através da seleção dos indivíduos mais resistentes.
13
Skår, Torstein. "Ice induced resistance of ship hulls : A comparison of resistance estimated from measurements and analytical formulations." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-15485.
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Due to global warming and hydrocarbon exploration in the Arctic areas, there is an increasing maritime activity in ice infested waters. Today one can with good accuracy predict if a vessel will be able to survive an encounter with ice of a given thickness, but the knowledge is not good enough to predict the increased fuel cost for ice navigation. This thesis has investigated the validity of two analytical formulations for ice resistance in Arctic areas. The formulations are based on full-scale ice trials in the Finnish-Swedish waters, which have lower salinity and warmer climate than the Arctic areas. This is done by comparing the resistance estimated from onboard measurements of vessel speed, ice thickness and engine power with the estimates from the analytical formulations. The ratio between the two is investigated using statistical tools. While most of the data have too much variation for any conclusions to be made, some time sequences without large variation in the resistance has been identified. Analysis from these sequences indicate that the formulation presented by Riska et al. (1997) appears to be able to describe the speed dependency of ice resistance in the Arctic, but is inaccurate when describing the ice thickness dependence. The formulation presented by Lindqvist (1989) is found to be inaccurate when describing both ice thickness and speed dependency. It is unclear whether the source of inaccuracy comes from incorrect ice property values or if the formulations have been used outside their area of application (both are based on ice trials in the Baltic Sea).
14
Liu, Gengshen. "Measurement of ship resistance coefficient from simple trials during a regular voyage." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14391.
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Moody, Robert D. "Preliminary power prediction during early design stages of a ship." Thesis, Cape Technikon, 1996. http://hdl.handle.net/20.500.11838/1261.
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Thesis (Masters Diploma (Mechanical Engineering)) -- Cape Technikon, Cape Town,1996A need exists whereby the preliminary power requirement of a ship can be rapidly estimated. Because the majority of methods available for this purpose are manual and consist of a number of independent components, they are tedious and time consuming to use. With the advent of the personal computer and its widespread acceptance, it was logical to examine the various components involved to determine their suitability for computerisation and general accuracy. In total eleven hull resistance prediction methods were examined, eight of which were computerised. Model test data of four vessels were used to evaluate these eight programs. The methodproviding the best results was selected to form the core of an integrated Power Prediction program. Factors such as appendage resistance, fouling and hull roughness were examined and appropriate methods selected for inclusion into the integrated program. Various propeller series were examined and evaluated against a variety of examples and model data. Two propeller optimisation programs were written and a general method for determining the optimum characteristics from Kr-KQ polynomials is described. Methods for determining propulsion coefficients were examined and their results compared with those obtained from model tests. The method providing the best overall results was incorporated into the Power Prediction program Added resistance due to sea state was broken down into two components, namely wind and wave resistance. Only the head sea and wind conditions were considered. Various methods for estimating wind resistance were examined and a program developed capable of providing resistance estimates regardless of wind direction. The problem of added resistance due to waves was examined and two programs written around the methods examined. To facilitate prediction estimates, sea state was chosen as the prime function. Wave height is estimated for the appropriate sea state and wind speed in turn from the wave height Actual sea trial data ofa twin screw channel ship is used to determine the overall accuracy ofthe Power Prediction Program
16
Islam, Z. "To investigate means of reducing added resistance due to the rudder and yawing in oblique weather." Thesis, University of Newcastle Upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234392.
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Demirel, Yigit Kemal. "Modelling the roughness effects of marine coatings and biofouling on ship frictional resistance." Thesis, University of Strathclyde, 2015. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=26005.
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The answers to the question, “How might the roughness of coatings and biofouling be related to full-scale ship resistance and powering?” were sought in this research, and novel contributions were made to the state-of-the-art knowledge. The current techniques used for predicting the roughness effects of marine coatings and biofouling on the resistance of full-scale ships rely on assumptions from similarity law scaling and boundary layer theory. Although this is a reasonable method, it may be difficult for less experienced users to carry out such an analysis since similarity law scaling includes several numerical procedures which may cause numerical errors and requires deep knowledge of the subject. It would also be beneficial to propose alternative methods with which to accurately predict these effects using fully-nonlinear Computational Fluid Dynamics (CFD) models, since current technological advances offer computational power which can be utilised to perform simulations based on Reynolds-Averaged Navier-Stokes (RANS) approaches. This work mainly aims to model the roughness effects of marine coatings and biofouling on ship resistance and powering, and to develop and propose alternative models for this purpose. Firstly, drag characterisation of several marine coatings, including the novel paints developed within the EU FP7 FOUL-X-SPEL Project, as well as control surfaces, was made through towing tests of flat plates coated with such coatings. An in-house code based on the similarity law scaling was then developed. This was used to assess the roughness effects of different marine coatings, including FOUL-X-SPEL Paints, and different fouling conditions on the frictional resistances of flat plates of ship lengths. Added resistance diagrams were generated using these predictions. Following this, two separate CFD models were developed and proposed for the prediction of the roughness effects of marine coatings and biofouling using flat plates of both model-scale and full-scale. These models were validated against an experiment and compared with the similarity law scaling, respectively. Afterwards, unsteady RANS CFD simulations of the roughness effects of marine coatings and biofouling on the full-scale KCS hull appended with a rudder were performed, using the roughness models proposed earlier, in order to arrive at a final conclusion. Finally, some discussions and conclusions on the outcomes of the work performed within this thesis are presented. This author believes that this study has shown the applicability of the CFD-based method to investigate the roughness effects of marine coatings and biofouling on ship frictional resistance. The CFD methods and added resistance diagrams proposed in this thesis stand as practical prediction methods for both academia and industry.
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AGENO, EMANUELA. "Ship Motions and Added Resistance with a BEM in frequency and time domain." Doctoral thesis, Università degli studi di Genova, 2019. http://hdl.handle.net/11567/944942.
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This thesis is focused on the calculation of ship motions and on the evaluation of added resistance
in waves. A partial desingularized panel method based on potential theory has been
developed.
Rankine sources are distributed on the hull and at small distance above the free surface.
In such way only the free surface is desingularized. This choice allows to consider also thin
hull shapes at the bow where desingularization could cause numerical problems.
The main advantage of this approach leads to reduce the computational time, especially when
non linear effects are considered, provided an adequate source-panel center vertical distance
is selected.
The fluid domain boundaries have been represented as a structured grid consisting of flat
quadrilater panels.
In the linear case the boundary conditions have been applied on the mean body wetted surface
and the free-surface is considered at the calm water level. By using an Eulerian timestepping
integration scheme the kinematic and dynamic boundary conditions are updated on
the free-surface at every time-step. After the potential is obtained, the pressure on the mean
hull surface can be calculated and forces and moments can be determined by integrating the
pressure on the body surface.
Therefore in two-dimensional environment an introduction of non-linear effects has been
analysed. In particular a 2D body exact method has been developed.
The added resistance is determined by a near field method integrating the second-order pressure
on the body surface. Then it is corrected using a semi-empirical method to allow to consider
the wave reflection of short waves.
The adequacy of the results has been verified applying the code to different test cases and
comparing the numerical output with experimental data available in literature. Furthermore in
order to discuss the improvements obtained with this present method the results have been
compared with another numerical method in frequency domain.
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Stocker, Mark Ryan. "Surge free added resistance tests in oblique wave headings for the KRISO container ship model." Thesis, University of Iowa, 2016. https://ir.uiowa.edu/etd/2148.
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Surge Free Added Resistance testing in variable head wave conditions were completed for a container ship model. The added resistance experiments include calm water, head wave, and oblique wave cases with a focus on establishing a validation benchmark for CFD codes computing the added resistance and motions of the ship model during maneuvering. The ship used is a 1/85.19 scale KRISO Container Ship, KCS, model with a length of 2.70 m. Tests were performed at the IIHR wave basin. The 20 x 40 x 4.5 m wave basin is equipped with 6 inline plunger type wave makers and a 3 degrees of freedom carriage. A 4 degrees of freedom, surge, heave, roll, and pitch free mount with a mass spring damper system was used to tow the model. Calm water tests were performed for 13 Froude numbers between 0.0867 and 0.2817. The resistance coefficients, sinkage, and trim were found for each test. The calm water results were obtained and compared to results from towing tank facilities, with traditional mounts, to estimate facility biases at the IIHR wave basin. The results show that the size difference of the IIHR model and surge free motion create magnitude differences between facilities. Head and oblique wave tests were performed at Froude number 0.26 and wave height to wavelength ratio, H/λ, of 0.0167. For all wave tests, time histories of wave amplitude, resistance, and 4 DOF were measured. Fourier analysis was completed for all time histories of waves, forces, and motions and the 0th, 1st, and 2nd harmonic amplitudes and phases are presented. All head wave results are compared to other facilities data taken in a towing tank with a traditional mount. The data from all wave heading data was analyzed with a focus on the trends with incremented wave encounter angle. Most harmonic amplitudes show good agreement between all facilities, but removal of the small model used by IIHR shows even better agreement between facilities. The oblique wave heading data shows good agreement with the only other experimental oblique wave added resistance testing. Complete uncertainty analysis was completed for select cases for calm water, head wave, and oblique wave conditions. The uncertainty showed accurate data form most wavelength settings.
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Linde, Florian. "3D modelling of ship resistance in restricted waterways and application to an inland eco-driving prototype." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2389/document.
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Les travaux de cette thèse ont pour but de développer un prototype d’éco-pilote, nommé EcoNav, permettant d’optimiser la vitesse d’un bateau afin de réduire sa consommation de carburant. EcoNav est composé de plusieurs modules dont : un modèle hydraulique 2D simulant l’écoulement hydrodynamique (vitesse du courant et hauteur d’eau) le long du trajet du bateau; - un modèle de résistance à l’avancement servant à alimenter un modèle de prédiction de la consommation de carburant; - un algorithme d’optimisation permettant de trouver le profil optimal de vitesse. Afin de pouvoir estimer la consommation de carburant, un modèle numérique de la résistance à l’avancement en milieu confiné a été développé durant la première partie de cette thèse. Ce modèle numérique 3D simule l’écoulement du fluide autour du bateau et permet de calculer les forces agissant sur sa coque. La résolution des équations RANS est couplée avec un algorithme de quasi-Newton afin de trouver la position d’équilibre du bateau et calculer son enfoncement. Cette méthode est validée en comparant les résultats numériques avec des résultats expérimentaux issus d’essais en bassin de traction. L’influence de l’enfoncement sur la résistance à l’avancement et la précision de la méthode est étudiée en comparant les résultats numériques obtenus avec et sans enfoncement. La précision des modèles empiriques de prédiction de la résistance à l’avancement est également comparée à celle du modèle numérique. Enfin, le modèle numérique est utilisé afin de déterminer si le confinement en largeur ou en profondeur ont une influence identique sur l’augmentation de résistance à l’avancement. Les résultats de cette étude permettent d’établir si le confinement de la voie d’eau peut être caractérisé à l’aide d’un paramètre unique (coefficient de blocage par exemple) ou bien deux paramètres permettant de distinguer le confinement latéral et vertical. Dans la seconde partie de cette thèse, les méthodes numériques utilisées pour le modèle d’éco-pilote sont décrites et comparées afin de sélectionner celles qui sont le plus adaptées à chaque module. EcoNav est ensuite utilisé afin de modéliser un cas réel : celui du bateau automoteur Oural navigant sur la Seine entre Chatou et Poses (153 km). La consommation optimisée est comparée à la consommation non optimisée, calculée à partir des vitesses AIS observées sur le tronçon étudié. L’influence de la trajectoire du bateau et de son temps de parcours sur sa consommation sont également étudiés. Les résultats de ces investigations ont montré qu’optimiser la vitesse du bateau permet d’obtenir une réduction de la consommation de carburant de l’ordre de 8 % et qu’optimiser la trajectoire du bateau ainsi que prendre en compte des informations en temps réel (disponibilité des écluses, trafic sur le fleuve) peuvent permettre de réaliser des économies de carburant supplémentairesAn eco-driving prototype, named EcoNav, is developed with the aim of optimizing a vessel speed in order to reduce fuel consumption for a given itinerary. EcoNav is organized in several modules : - a 2D hydraulic model simulating the flow conditions (current speed and water depth) along the itinerary; - a ship resistance model calculating the thrust necessary to counteract the hydrodynamic forces ; - a fuel consumption model calculating the fuel consumption corresponding to the thrust input; - a non linear optimization algorithm calculating the optimal speed profile. In order to evaluate the fuel consumption of an inland vessel, a ship resistance numerical model is developed in the first part of this PhD. This 3D numerical model simulates the flow around an inland self-propelled vessel and evaluates the hydrodynamic forces acting on the hull. A RANS solver is coupled with a quasi-Newton approach to find the equilibrium position and calculate ship sinkage. This method is validated by comparing the results of numerical simulations to towing tank tests. The numerical results with and without sinkage are also compared to study the influence of sinkage on ship resistance and on the accuracy of the method. Additionally, some empirical models are investigated and compared with the accuracy of the numerical method. Finally, the numerical model is used to determine if channel with and water depth restriction contribute to the same amount of ship resistance increase for the same level of restriction. The results of that investigation give insight to whether channel restriction can be characterized by a unique parameter (for instance the blockage ratio) or two parameters to distinguish water depth and channel with effects. In the second part of this PhD, the numerical methods used in the speed optimization model are described and validated. The speed optimization model is then used to simulate a real case: the itinerary of the self-propelled ship Oural on river Seine, between Chatou and Poses (153 km). The optimized fuel consumption is compared with the non-optimized fuel consumption, based on AIS speed profile retrieved on this itinerary. The effects of the ship trajectory and travel duration on fuel consumption are also investigated. The results of those investigations showed that optimizing the ship speed lead to an average fuel saving of 8 % and that using an optimal track and including real time information such as lock availability and river traffic can lead to additional fuel savings
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Morgan, Harith. "Design of a mechanism to increase lateral force resistance of an autonomous ship hull cleaning robot." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127897.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020Cataloged from the official PDF of thesis.
Includes bibliographical references (page 27).
Marine biofoul accrues on ship hulls and increases the resistance of a ship during voyage. This is a widespread issue within the shipping an industry -- which supports the vast majority of global trade. To address this problem, we are developing Bio-Inspired HullCrawler -- an autonomous robot capable of cleaning ship hulls while a ship is underway. The novelty of our design centers on the bio-inspired suction cups that are cast as composite silicon elastomer. The purpose of this thesis is to look specifically at the lateral force resistance of elastomeric suction cup mechanisms. Here we propose new design concepts for the attachment system to improve on the drag force resistance of the HullCrawler device.
by Harith Morgan.
S.B.
S.B. Massachusetts Institute of Technology, Department of Mechanical Engineering
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Gao, Qiuxin. "The effect of free surface on classical ship hydrodynamics using RANSE : resistance, manoeuvring, propulsion, seakeeping and stability." Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=16924.
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In this research, the Computational Fluid Dynamics (CFD) approach, based on the solution of the Reynolds Averaged Navier-Stokes (RANS) equations is used to study the classical ship hydrodynamic problems, all being affected markedly by the presence of free-surface, namely: ship resistance, propulsion, manoeuvring, seakeeping and stability, the latter focusing on flooding of a damaged ship. In this respect, this thesis represents a marked deviation from classical approaches and a unique contribution to ship dynamics and hydrodynamics. The RANS equations with SST K-w two-equation turbulence model and Volume Of Fluid (VOF) formulation were discretised by the finite volume (FV) method and the pressure-coupled governing equations were solved by the SIMPLE algorithm. The geometric reconstruction algorithm was adopted to locate transient free surfaces. The second order upwinding scheme was used for the discretisation of the convection flux and Multi-grid Acceleration was applied to improve convergence. In addressing ship resistance, grid sensitivity studies were carried out according to the “ITTC guideline of quality” manual. The computed results were verified and validated against available model test data. Additionally, the results of the effects of the turbulence models were investigated by comparing turbulence quantities predicted by SST K-w and RSM. In addressing ship propulsion, the propeller was modelled as an actuator disk of equivalent thrust and torque. Distributions of the body force were compared with results from a parametric study and the implementation of the body force approach was validated by model test data. In addressing ship manoeuvring, numerical PMM simulations of pure sway and yaw motions were performed. The numerical results were benchmarked against physical experiments. The computed hydrodynamic derivatives were compared with empirical formulae and subsequently implemented in manoeuvring simulations. In addressing seakeeping, incident waves were generated by a numerical wave maker and the computed results for wave diffraction were validated against physical measurements. Furthermore, RANS simulation for roll decay was undertaken and validated against results from model tests. Finally, a numerical roll tank was established to study the hydrodynamic coefficients of the roll motion in intact and damaged conditions and the corresponding results were compared with available model test data. In conclusion, systematic studies and ensuing results from numerical simulations of classical ship hydrodynamic problems using RANS demonstrated beyond doubt that CFD could and should play an important role in the design, analysis and evaluation of ship hydrodynamic performance. In addition, they provide unshakeable evidence of the level of capability to make the next important step: rendering CFD a routine "tool" in ship dynamics and hydrodynamics.
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Little, Patrick E. (Patrick Edward). "A study of the wedge cutting force through transversely stiffened plates : an application to ship grounding resistance." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/37522.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1994, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1994.Includes bibliographical references (leaves 115-117).
by Patrick E. Little.
M.S.
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Paterson, Angus John Cawood. "A study of ship wave resistance from an analysis of the wave pattern using close range photogrammetry." Master's thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/15822.
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Bibliography: pages 156-162.In this thesis the wave pattern generated by a moving ship is investigated experimentally using close range photogrammetry. The author has been primarily interested in validating a new approach in the determination of the wave making resistance of a ship by means of the energy contained within the wave pattern. Secondary considerations were the measurement of the total ship resistance and other dynamically related applications; squat and trim, bow and stern wave profiles and their interactive effects. The proposed theoretical approach in this analysis of the wave resistance from the wave pattern is essentially phenomenological. As a ship proceeds through the fluid, it generates a set of waves radiating from the bow and stern due to the pressure differences along the hull. Energy is needed to maintain this system and is supplied at a constant rate by the ship, this being the energy required to overcome wave-making resistance. If the total change in energy within the wave pattern can be evaluated over a time interval associated with a known ship movement, then the energy difference will be a related to the wave making resistance.
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Huang, Zhaoyuan. "Ship-waves modelling and their interactions with inland waterways." Electronic Thesis or Diss., Compiègne, 2022. http://www.theses.fr/2022COMP2686.
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Le sujet de thèse concerne la Modélisation de l’impact de la navigation fluviale sur la voie navigable par les méthodes CFD, en utilisant OpenFoam. Dans la première partie de la thèse, l’hydrodynamique des navires en milieux confinées a été étudiée. Elle consiste en la caractérisation de l’écoulement autour du navire et la génération des vagues de batillage en fonction des caractéristiques géométriques et cinématiques du bateau et également des caractéristiques géométriques du chenal de navigation. Pour cela, une étape de modélisation numérique adaptée à la navigation en milieux confinés, qui concerne le choix du type de maillage, de schéma numérique, etc.., a été élaborée. La deuxième partie est consacrée (i) tout d’abord à la validation et la comparaison des résultats numériques avec les mesures expérimentales en laboratoire du CNR (Compagnie Nationale du Rhône) (ii) ensuite à l’examen de la résistance à l’avancement du bateau suivant différentes configurations géométriques du canal de navigation (largeur, profondeur d’eau, etc.…) (iii) enfin, à la modélisation des processus du Sinkage et du Trim du bateau et à leur influence sur la résistance à l’avancement du bateau. Outre les dimensions géométriques du canal de navigation, l’enfoncement, le tirant d’eau, et la vitesse du bateau ont été également pris en compte pour étudier leur influence sur la résistance à l’avancement. La troisième partie de la thèse est consacrée à l’étude de l’influence des vagues d’étrave et des ondes de batillage générées par le déplacement des bateaux sur les berges des voies navigables et notamment sur la stabilité des blocs de protection des berges. Les blocs forment ici un milieu discret et sont considérés comme des corps rigides susceptibles d’entrer en collision les uns avec les autres et avec les berges. Ainsi, dans cette partie, un modèle de corps rigides à 6 Degrés de Liberté (6DoF), qui tient compte de la forme des blocs, a été utilisé pour (i) tenir compte des processus de contact et de collision solide-solide et solide-bords rigides et pour (ii) étudier la stabilité de la berge, en se basant sur la moyenne des mouvements des blocsThe subject of this thesis concerns the investigation of ship hydrodynamics, shipinduced wave modeling, and wave-bank interactions in restricted waterways by CFD approaches based on OpenFOAM. The first part of this thesis is focused on the study of the hydrodynamics of ships in a restricted environment. This consists of the characterization of the flow around the ship and the generation of waves according to the geometric and kinematic characteristics of the ship and also the geometric characteristics of the waterway channel. To this end, the steps of numerical modeling adapted to navigation in a confined environment, which concern the preference of meshgeneration, numerical schemes, etc., was developed. The second part is devoted (1) first to the validation and comparison of the numerical results with the experimental measurements from the laboratory of the CNR (Compagnie Nationale du Rhône) are carried out; (2) next to the examination of the ship’s forward resistance according to different geometric configurations of the waterway channel (width, water depth, slope, etc.) (3) finally, to the implementation of a six-degree-of-freedom model (6DoF) to assist in the modeling of the sinkage and trim processes of ships in restricted waterways. Meanwhile, the critical effects of ships under different speed conditions in restricted environments were also researched and analyzed. The third part of the thesis deals with the study of the influence of waves induced by ships on the banks of inland waterways and in particular on the stability of the bank protection blocks. The erosion effect caused by the impact and shear of ship-induced waves on the exposed river bank was studied. The armor protection layer on the river bank is composed of discrete blocks and these blocks are regarded as rigid bodies that can collide with each other and with the banks. Thus, in this part, a CFD-DEM solver, SediFoam, was applied to (1) take into account the solid-solid and solid-boundary of domain rigid contact and collision processes and (2) investigate the stability of the rocky layer of banks, based on the average of the movements of the blocks
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Saunders, Robert P., and Charles Natale Calvano. "An investigation of the resistance properties of a modern trimaran combatant ship based on Taylor Standard Series and Series 64." Thesis, Monterey, California. Naval Postgraduate School, 1995. http://hdl.handle.net/10945/7477.
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Medhurst, John Stephen. "The systematic measurement and correlation of the frictional resistance and topography of ship hull coatings, with particular reference to ablative antifoulings." Thesis, University of Newcastle Upon Tyne, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.346447.
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Du, Peng. "Numerical modeling and prediction of ship maneuvering and hydrodynamics during inland waterway transport." Thesis, Compiègne, 2018. http://www.theses.fr/2018COMP2459.
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Dans cette thèse, l'hydrodynamique des navires lors du transport par voies navigables et des manœuvres sont étudiées à l'aide de la CFD (Computational Fluid Dynamics) basée sur OpenFoam. Des études de validation et de vérification sont réalisées pour la convergence de maillage, la convergence de pas de temps, la sensibilité aux modèles de turbulence et les techniques de maillage dynamique. Un solveur de mouvement 6DoF basé sur quaternion est mis en œuvre pour les prédictions d'assiette et d'enfoncement. Les effets environnementaux sur plusieurs bateaux de navigation intérieure (convoi 1, convoi 2, automoteur) sont étudiés à l'aide de modèles numériques validés. Trois aspects importants sont simulés: l'effet de confinement de la voie navigable, le croissement et l'interaction bateau-pile de pont. Les conditions d’essai couvrent un large éventail, y compris les différentes dimensions du canal, la profondeur de l’eau, le tirant d'eau et la vitesse. La résistance du navire, le type de vague, l’angle de Kelvin et l’élévation de la vague à des positions spécifiques sont étudiés en fonction de ces paramètres. La manœuvre des navires est étudiée à l’aide de tests de modèles captifs virtuels basés sur le modèle MMG (Mathematical Maneuvering Group). Un disque d'actionneur est implémenté pour remplacer l'hélice réelle. Les tests d'un modèle KVLCC2 sont effectués pour obtenir les coefficients hydrodynamiques de l'hélice, du gouvernail et de la coque du navire. En utilisant les coefficients obtenus, des simulations de manœuvre sont effectuées et validées. Ces études reproduisent des tests de navires réels et prouvent ainsi la validité de nos modèles numériques. En conséquence, le solveur numérique est prometteur dans les simulations d'hydrodynamique des navires et d'ingénierie marineIn this thesis, the ship hydrodynamics during inland waterway transport and ship maneuvering are investigated using CFD (Computational Fluid Dynamics) based onOpenFoam. Validation and verification studies are carried out for the mesh convergence, time step convergence, sensitivity to turbulence models and dynamic mesh techniques. A quaternion-based 6DoF motion solver is implemented for the trim and sinkage predictions. Environmental effects on several inland vessels (convoy 1, convoy 2, tanker) are studied using the validated numerical models. Three important aspects, the confinement effect of the waterway, head-on encounter and ship-bridge pile interaction are simulated. The testing conditions cover a wide range, including various channel dimensions, water depths, ship draughts and speeds. The ship resistance, wave pattern, Kelvin angle and wave elevation at specific positions are investigated as functions of these parameters. Ship maneuvering is investigated using virtual captive model tests based on the MMG (Mathematical Maneuvering Group) model. An actuator disk is implemented to replace the real propeller. Open water test, rudder force test, OTT (Oblique Towing Tank test) and CMT (Circular Motion Test) of a KVLCC2 model are carried out to obtain the hydrodynamic coefficients of the propeller, rudder and ship hull. Using the obtained coefficients, system-based maneuvering simulations are carried out and validated using the free running test data. These studies reproduce real ship tests and thus prove the validity of our numerical models. As a result, the numerical solver is promising in ship hydrodynamics and marine engineering simulations
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Alvarez, Rodrigo Loureiro Prado. "Otimização das formas de cascos de deslocamento em relação a sua resistência ao avanço." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3135/tde-31032008-171045/.
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Devido à constante necessidade de construções de novas embarcações, quer seja pela demanda do mercado, quer seja pela renovação da frota, o desenvolvimento de programas computacionais que auxiliem na fase inicial de projeto torna-se bastante útil. Assim, o desenvolvimento de um procedimento de análise que permita obter formas de melhor desempenho vem a agregar valor nesta etapa de conceituação da geometria do navio. O trabalho aqui apresentado tem como objetivo discorrer sobre um método capaz de otimizar a geometria de um casco de deslocamento conhecido em relação a sua resistência ao avanço, sem perder, porém, as suas características principais, como corpo paralelo médio, por exemplo. Para tanto, dentro deste processo de otimização já estão inseridas algumas restrições que garantem a viabilidade da solução final, tais como variação máxima no comprimento, no volume total e na estabilidade do navio. A modelagem da embarcação pode ser feita através de funções B-Splines cúbicas de superfície, cujos pontos de controle (parâmetros inerentes à função) podem ser modificados de tal sorte a atingir um valor ótimo para a resistência ao avanço. Esta, por sua vez, será obtida através da soma de duas parcelas, sendo uma referente ao atrito e outra à geração de ondas pelo casco. Como a maior parte da resistência provém desta segunda parcela para a velocidade de projeto a ser considerada (alto número de Froude), a redução da resistência total pode ser assumida como conseqüência da diminuição da resistência devido à geração de ondas, a qual pode ser obtida através da formulação apresentada por Michell, em 1898. O cálculo das propriedades hidrostáticas como deslocamento, estabilidade ( KM transversal) e superfície molhada, usada para cálculo da resistência ao avanço, pode ser encontrado fazendo-se uso do cálculo vetorial. O procedimento a ser descrito foi desenvolvido em linguagem C++ (modelagem do casco) e com o auxílio do MATLAB® (método de otimização). Este trabalho foi realizado no Dep. de Eng. Naval e Oceânica da USP.Due to an increasing necessity of building new vessels, whether by new orders or fleet renewal, the development of computational programs that could allow optimization of hull shapes is always helpful, saving project time and ensuring better performance at sea. Thus, the development of a synthesis procedure that allows obtaining shapes with better performance adds value to the initial phase of the ship geometry concept. The work to be presented herein objectives the presentation of a methodology to achieve optimal shapes for displacement hulls in relation to the total resistance, starting from an initial geometry given, describing hull form and applying specific constraints to optimization problem with the purpose of guarantee a reliable solution. Therefore, inside this optimization process there are included some constraints that ensure a feasible final solution, as maximum variation of ship length, total volume and stability. Hull geometry is described by using B-Spline surface functions and the ship wave resistance is calculated using Michell\'s formulation as a first approximation of the total resistance for high Froude numbers. Once vessel surface is well defined, B-Spline parameters are varied until an optimal form is attained and the minimum resistance is achieved. It can take a little time to calculate, depending on ship definition (number of buttocks and waterlines) and the problem complexity (number of constraints and variables). Ship displacement and other hydrostatic properties as stability, given by transversal KM , wetted surface, used for calculating ship resistance, can be obtained using the vectorial calculus. This work has been developed using C++ language, except the optimization process which makes use of a MATLAB® function called fmincon. This study has been held at the Department of Naval and Ocean Engineering of the University of São Paulo, Brazil.
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Caplier, Clément. "Étude expérimentale des effets de hauteur d'eau finie, de confinement latéral et de courant sur les sillages et la résistance à l'avancement des navires." Thesis, Poitiers, 2015. http://www.theses.fr/2015POIT2315/document.
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Ce mémoire présente une étude expérimentale des effets de confinement de la voie d'eau et de courant sur les sillages et la résistance à l'avancement des navires. Deux formes de carènes génériques et représentatives de navires maritimes et fluviaux ont fait l'objet de mesures dans le bassin des carènes de l'Institut Pprime dans différentes configurations bathymétriques. Des méthodes de mesure de déformée de surface libre par moyens optiques stéréoscopiques ont été mises en place pour caractériser les sillages générés. L'étendue spatiale et la résolution des mesures optiques permet de mener une analyse fine du sillage dans l'espace spectral, afin de le décomposer en une composante hydrodynamique dans le champ proche de la carène et une composante ondulatoire dans le champ lointain. Les résultats obtenus dans une configuration de voie d'eau profonde mettent en évidence la non-linéarité des sillages. Les résultats obtenus dans une configuration de voie d'eau peu profonde mettent en avant une modification de la forme des sillages et une répartition différente de l'énergie entre les différents systèmes de vagues. L'influence de la forme et de la vitesse des navires sur l'amplitude de la réponse hydrodynamique et du courant de retour est mise en avant. Des mesures en présence de contre-courant montrent une augmentation de l'amplitude des vagues du sillage et un élargissement de la zone de réflexion au niveau des parois du canal. Des mesures de forces de traînée avec un dynamomètre donnent accès aux courbes de résistance dans chaque configuration. L'augmentation de la résistance à l'avancement en eau peu profonde est mise en parallèle avec l'augmentation de l'amplitude et de la longueur d'onde des ondes transversesThis thesis presents an experimental study of the effects of the waterway confinement and the current on ships wakes and drag. Two generic hulls representative of maritime and river ships have been studied in several bathymetric configurations in the towing tank of the Institut Pprime. Optical measurement methods based on a stereovision principle have been set up to measure the free surface deformations. The spatial extent and the resolution permits to lead a fine analysis of the wakes in the spectral space in order to decompose them into a hydrodynamic component and an undulatory component, respectively in the near-field and the far-field of the ship hull. The results obtained in a deep waterway configuration highlight the non-linearity of the ship wakes, which results in a modification of the shape of the envelop of the wave field in the real space. The results obtained in a shallow waterway configuration show a modification of the shape of the ship wakes and a different distribution of the energy between the wave systems. The influence of the shape and the speed of the ships on the amplitude of the hydrodynamic response and the return current is also identified. The comparison of the measurements in the presence of a counter-current with the results in calm water show an increase of the amplitude of the waves and an enlargement of the wash zone on the walls of the canal. Drag forces measurements with a multicomponent dynamometer give access to resistance curves for each configuration. The increase of the ship resistance in shallow water is put in parallel with the increase of the amplitude and the wavelength of the transverse waves
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Zhou, Zhengquan. "A theory and analysis of planing catamarans in calm and rough water." ScholarWorks@UNO, 2003. http://louisdl.louislibraries.org/u?/NOD,45.
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Thesis (Ph.D)--University of New Orleans, 2003.Title from electronic submission form. "A dissertation ... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Engineering and Applied Science"--Dissertation t.p. Vita. Includes bibliographical references.
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Rahman, Md Mosfiqur. "Structural resistance of polar ships and FPSO´s to ice loading." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18633.
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Due to the substantial increase in oil and gas activities in Polar areas the demand for ice strengthen vessel has increased greatly. This increase in demand has highlighted the importance of designing ice strengthened ship structures that are more producible and maintain adequate safety and integrity. In order to encounter these new challenges, the international association of classification societies (IACS) has developed unified regulations for the designing of ice strengthened ship. In addition to these requirements, most of the classification societies have their regulation for design of polar ships. Stiffened plates are the basic structural building blocks of ships. So, the study mainly explores the plastic response of stiffened plate subject to lateral ice loads. The Non Linear Finite Element Method (NLFEM) is extensively used to study the plastic behavior of stiffened plates. The Abaqus non linear finite element program is used in this study.The aims of the study are to investigate the validity of the limit state equation employed in the IACS new Unified Requirements for Polar Ships [6], investigate the membrane effect at large deformation, determine the ALS design load, and assess limit loads when fracture in plating likely to take place. The study also focuses on the warping effect of unsymmetrical sections and the effect of end brackets on the lateral load carrying capacity of the stiffener. The effect of mid-span tripping bracket on the load deflection behavior of L and T stiffeners is also studied. In particular, the study focuses on the behavior of inclined T and L stiffener. As ships move forward by crushing ice, sides of ships’ bow come across with ice initially. To design ice strengthen vessel, it’s very important to understand the behavior of ships’ side structure subjected to ice loads. So, this study extensively focuses on the non-linear finite element analysis of ships’ side structure subjected to ice loads. Normally, ship design rules are based on the behavior of single frame subjected to loads. It’s reasonable to consider frames singly under the uniform loading but in case of ice loading which is non uniform, the behavior of the structure obtained from single frame based design does not accurately represent the true behavior of the structure. The load-deflection characteristic of frames in isolation, frames as part of a ½+1+½ frames and frames as part of a grillage subjected to unsymmetrical loading is studied. As, stiffeners in the side structure of ships’ bow are not normally perpendicular with shell plate, the lateral capacity of frames as part of a ½+1+½ frames and as part of a grillage is obtained for inclined stiffener.The analyses in this study cover the full range of stiffener behavior from elastic, through yield, through the formation of initial mechanisms, through large deformations. The parameters considered for the analyses are: •frame profile: Angle, Tee•frame span•load length: patch (transverse), uniform (longitudinal)•web thickness•end brackets: with, without•Angle of inclination of stiffener web with the plate flange•Tripping bracket at mid span
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LeBlanc, David. "Fire Environments Typical of Navy Ships." Digital WPI, 2002. https://digitalcommons.wpi.edu/etd-theses/610.
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Current test methodologies used to evaluate the performance of protective clothing do not adequately determine the provided level of protection. The heat fluxes imposed by current evaluation methods are not specifically related to fire environments typical to those the clothing is designed provide protection against. The U.S. Navy is in the process of developing an improved process for testing the fire resistance of daily wear uniforms and protective gear. The first phase of this project involves evaluating currently used evaluation methods and identifying the severity of fire environments that would be expected aboard Navy ships. The examination of the test protocols currently in use identifies major weaknesses, providing the justification for a new test protocol. The first step in developing an improved test protocol is to determine the types of fire scenarios that would be expected aboard Navy vessels. The nearly infinite number of possible fires are reduced to 6 typical cases involving spray fires, pool fires and furniture fires in both compartmented and unconfined cases. An analysis of the environments produced by these types of fires is presented. The effects of compartmentation parameters are also investigated to determine the critical factors that affect the expected fire environment. Expected heat fluxes for all scenarios are presented at a number of distances from the fire.
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Martinot-Lagarde, Vincent. "An integral turbulent boundary-layer method and the residuary resistance of ships." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13042.
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Robert, Marie. "Modélisation numérique du comportement hydroélastique des navires sur houle non linéaire." Thesis, Ecole centrale de Nantes, 2017. http://www.theses.fr/2017ECDN0047.
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Avec l’accroissement de la taille des navires marchands de type porte-conteneurs, les interactions entre la réponse de tenue à la mer classique et la réponse structurelle sont de plus en plus présentes. Les fréquences propres de réponse structurelle de la poutre navire se rapprochent des fréquences de houle océaniques. La modélisation des interactions houlestructure devient un enjeu clé dans les étapes de design par les architectes et de validation par les sociétés de classification. Dans ce contexte, on se propose de développer un nouvel outil d’interaction fluide-structure associant une modélisation RANSE de l’écoulement en différences finies sous ICARE-SWENSE, code développé conjointement par le LHEEA et la société HydrOcéan, et un modèle de poutre analytique, le tout dans le cadre d’une approche modale. Grâce à l’emploi d’une formulation simple pour le traitement de la structure, l’outil de couplage hydroélastique sur houle hérite des propriétés de tolérance aux grands pas de temps d’ICARE-SWENSE, tout en prenant en compte les effets hydrodynamiques non linéaires. Les résultats présentés sur des cas de barge en diffraction et en radiation suivant les modes de déformation élastique permettent de valider les premières étapes de la mise en place du couplage. Une attention particulière est portée sur les seuils d’apparition des non linéarités de l’écoulement et leur impact sur la réponse structurelle. Une première implémentation est proposée pour la résolution du modèle libre des modes élastiques. Des études paramétriques de résistance ajoutée sur houle régulière et bichromatique viennent compléter les travaux dans la perspective de futurs calculs sur houle irrégulièreThe increase of large ships dimensions shifts their structural natural frequencies towards common wave frequencies, inducing more interactions between the classic seakeeping response and the structural response. Accurate modeling of wavestructure interactions becomes a key issue for architects and classification societies during the design of a ship. In this respect, a new numerical tool for fluidstructure interaction is developed, combining a finite difference RANSE description of the fluid domain with ICARE-SWENSE and an analytic beam model, within a modal approach. Thanks to the use of a simple formulation for the structure part, the tool inherits ICARE-SWENSE tolerance properties with regard to large time steps, while still taking into account hydrodynamic nonlinear effects. Results presented for a flexible barge in diffraction and radiation according to flexible modes validate the first steps of the coupling procedure. Special consideration is given to hydrodynamic non linearities threshold and their impact on the structural response. A first implementation is shown for the resolution of the equation of motion for the elastic degrees of freedom. Parametric studies on ship resistance in both regular and bichromatic waves are included as a stepping stone towards future simulations of ship hydroelasticity in irregular waves
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Carter, Frances Hannah. "Magic toyshops : narrative and meaning in the women's sex shop." Thesis, Kingston University, 2014. http://eprints.kingston.ac.uk/28758/.
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The sex shop aimed primarily at the female consumer is a phenomenon which forms part of our everyday understanding of the sexualisatian of culture or the mainstreaming of sexual representation and consumption. The women's sex shop privileges notions of female empowerment achieved through the consumption of goods and spaces dedicated to the pursuit of female erotic pleasure. Prioritising women's interpretations of the visual presence of the women's sex shop, this project establishes how the sex shop is re-made for its female consumers, making it both acceptable and desirable to a new audience. Primarily its aim is to interrogate the ways in which design is put to use to reflect, materialise and contribute to discourse around feminine sexuality and sexual pleasure. Utilising a feminist research methodology this thesis takes as a starting point the voices of women consumers and retailers, facilitating a new reading of the ways in which women negotiate the meanings invested in the spaces of gendered sexual consumption. In line with the testimony of participants, investigation begins by positioning the women's sex shop in relation to its progenitor, the traditional male sex shop, the model without which the women's shop could not be envisaged or designed. Secondly it investigates the ways in which the design of the women's sex shop and its goods, appropriate or resist established , normative and classed representations of female sexuality expressed in the geographical position of the shops, the interior layout, the external façade and the use of visual references. In conclusion, drawing on consumer narratives, research exposes a visual and spatial symbiosis between the 'seedy' masculine and the stylish women's sex shop. Key tensions and contradictions are unearthed in the things and spaces of the women's shop, calling into question the notions of female sexual agency and empowerment it proposes.
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Ishida, Yuki. "Generation of a neutralization-resistant CCR5 tropic SHIV-MK38 molecular clone, a derivative of SHIV-89.6." Kyoto University, 2016. http://hdl.handle.net/2433/215969.
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Chandraprabha, Sattaya. "An investigation into the wave wash and wave resistance of high speed displacement ships." Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273871.
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Brown, Christian R. (Christian Randall). "Effect of hull-to-bulkhead flexible connection on blast resistance of double hulled ships." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/33434.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 65).
The use of double hull construction is commonplace within the shipping industry though it is largely unexploited within naval vessels. The Impact and Crashworthiness Lab at MIT has proposed the use of adaptive sandwich structures to improve the blast resistance of naval hulls. This project will address two main areas of investigation through the use of simplified analytical models: the integration of hardening and softening plastic core responses in the crushing of a rigidly supported sandwich panel; and the deformation analysis of a sandwich panel supported by non-rigid connections. The analytical solutions were utilized to perform a series of parametric studies to evaluate both the useable range of the models as well as to investigate the general behavior of a sandwich panel under a uniform load when supported by crushable connections. This initial investigation provides the simplified tools to begin and to validate a more detailed, numerical analysis.
by Christian R. Brown.
S.M.
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Madsen, Anders. "Estimation of Ice Resistance of Ships based on Measurements of Ice Thickness, Speed and Power." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11598.
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The activity in the polar marine areas is increasing from offshore and shipping activities supporting both commercial and tourist operations. Particular of interest is the expansion in offshore oil and gas exploration and productions activities in ice covered waters in the northern hemisphere. The presence of sea ice is the main factor for the complexity for operations in these regions. The presence of sea ice is the main factor hindering the operations in Arctic. Sea ice is a complex material, and induces high pressures in contact with ships or structures. Different types of sea ice and their mechanical and physical properties are briefly described. There exist different models for calculation of contact pressure acting on a vessel or a structure due to ice. This thesis will briefly present three different and popular approaches to predict ice pressure on structures and ships, namely; empirical pressure relationships, physical models and stochastic models. The best approach to predict ice pressure depends much on the problem and what kind of data that is available. Ice class rules for vessels operating in ice infested waters are reviewed. The ice-class rules developed by IACS and DNV are summarized, and both principles behind the rules and the numerical values have been compared. The main difference is that IACS us a plastic method of approach, while DNV uses an elastic method. Despite the difference in method of analyses, the numerical comparison shows they are relative similar. The IACS rules are typically most conservative for larger vessels with large displacement, while the DNV rules are conservative for smaller vessels with small displacement. A review of two different formulations for estimation of ice resistance for ship is given. This is inexpensive analytical models that can give an early estimation of the ice resistance and power requirement. Using main properties from KV Svalbard the two different formulations is compared, and they seem two compare quite well for thin ice (hi < 1m) when the vessel speed is low. For higher vessels speeds the results differs more from each other. The increasing activity in polar areas is the main motivation for Det Norske Veritas project Ice Load and Monitoring (ILM). The overall aim of the ILM-project is to increase the knowledge about the actual ice conditions a vessel meets and its effect on the hull. As a part of the project a prototype of a monitoring system was mounted on the coast guard vessel KV Svalbard, which is described. During research work with KV Svalbard for a total of two weeks in late March 2007 operating in ice covered waters around Spitsbergen, measurement from the ILM-system was stored for later usage. Based on conservation of energy a formulation is outlined to describe how the ice resistance can be estimated for a particular case. In this thesis KV Svalbard is used with available measurements of ice thickness, speed and power from the voyage in late March 2007. The estimated resistance is compared with the two reviewed formulations from literature, and the trend in the results seems to agree well. In the final task, a regression analysis was used to find the "best fit" line or curve to the estimated resistance of KV Svalbard. Different Least Square curves was evaluated and discussed and it was found out that an exponential curve fitted best to the estimated data.
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Shin, Dai-Lun [Verfasser]. "Studies on the Host Genetic Resistance and Susceptibility to Influenza A Virus / Dai-Lun Shin." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2015. http://d-nb.info/1073932885/34.
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Hadjiyiannis, Nicholas. "Projection of fractures in ships for the evaluation of fatigue resistant designs." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/55269.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 71-81).
Cracks in ships have been of great concern to the maritime industry for a very long time. The problem is controlled by improving design, minimizing operating stresses and through regular inspections and repairs. The big trade-off which designers and owners have to face in the construction of a new ship is whether to invest in a fatigue resistant design, or to keep the construction cost low and incur the repair costs as cracks emerge later in the ship's life. This choice has to be made for hundreds of components throughout the ship's hull. A procedure was developed to assess the cost effectiveness of fatigue design improvements in ships. It is based on comparing the additional cost of a proposed design (over the current design) with the present value of all the projected crack repair costs of the corresponding location. The present value of the repair costs has to be determined for the various locations in order to serve as a guideline when evaluating new fatigue resistant designs that promise to reduce the number of cracks and future repair costs. A general model was developed and then several assumptions were made to give a simplified version. The assumptions and limitations of the model are discussed as well as the ways in which it should be used to address various problems and produce meaningful results. Suggestions are also made for avoiding problems in each stage. A large database of cracks is required to run the model and a location coding system in order to process and analyze it..
(cont.) The difficulties of collecting and processing the data are discussed as well as potential adjustments that have to be made to accommodate irregularities among ships and ship compartments. A literature review was carried out of the various statistical surveys that have been conducted over the past 50 years relating to cracks and damages in ships. Differences in the results of surveys regarding the distribution of cracks lead to the conclusion that cracks follow different patterns than other damages and that the various kinds of ships exhibit different cracking behaviors. This emphasizes the importance of using a large data sample that is specific to a particular type of damage and ship type and size range when applying this proposed model and procedure.
by Nicholas Hadjiyiannis.
S.M.
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Descamps, Théo. "Numerical analysis and development of accurate models in a CFD solver dedicated to naval applications with waves." Thesis, Ecole centrale de Nantes, 2022. http://www.theses.fr/2022ECDN0049.
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L’objectif de cette thèse est de développer des solveurs numériques et des méthodologies afin d’améliorer le temps de calcul et la précision des simulations de tenue à la mer et de résistance ajoutée sur houle. Tout d’abord, une synthèse de l’algorithme du solver foamStar développé en interne est effectuée. A partir de cette analyse, une modification est proposée afin de pouvoir utiliser le "Multidimensional Universal Limiterfor Explicit Solution" (MULES) avec un schéma temporel backward d’ordre deux. Ensuite, plusieurs études successives sont réalisées afin de : vérifier l’implémentation du schéma backward ; définir une configuration numérique et des maillages efficaces pour la simulation de houle. Les cas d’étude sont : les tourbillons de Taylor-Green, la houle régulière non linéaire se propageant dans un domaine periodique, et enfin, la houle régulière générée avec des zones de relaxation et des configurations numériques proches de celles utilisées pour des applications navales. Dans la dernière partie de cette thèse, une étude préliminaire est réalisée en simulant un porte-conteneur avec une vitesse d’avance dans des houles régulières de face. Les recommandations définies tout au long de cette thèse sont également évaluéesThe objective of the present thesis is to develop solvers and methodologies in order to improve the computational cost andthe accuracy with regard to the thematics of seakeeping and added resistance. First, a synthetic workflow of the algorithmof the in-house solver foamStar is proposed. From this analysis a modification is proposed in order to use the Multidimensional Universal Limiter for Explicit Solution (MULES) with a second-order backward time scheme. Then, successive studies are done in order to: verify the implementation of the backward scheme; define an efficient numerical set-up and adequate mesh structures for numerical wave simulations. The case studies are, Taylor-Green vortices, nonlinear regular wave propagating in a periodic domain, and finally, regular waves generated with relaxation zones considering numerical configurations close to what is used for naval applications. In the last part of this Thesis, a preliminary study is done simulating a containership with forward speed in head regular waves. The recommendations derived all along this thesis are also evaluated
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Saleh, Jehan. "The making of a resistance identity : communism and the Lebanese Shiʿa, 1943-1990." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/28693.
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This is a study of the identities and political mobilisation of the Lebanese Shiʿa throughout the modern history of Lebanon. Currently, the dominant paradigms for such studies focus on the question of sectarianism in Lebanon and the corresponding Shiʿi political movements, Amal and Hizbullah. This thesis presents an alternative approach. It argues that secular identities have also been an important component of the Shiʿi community’s political mobilisation. This is explored through an analysis of the relationship between the Lebanese Communist Party (LCP) and the communist Shiʿa. Drawing on interviews with senior LCP officials, current and former Shiʿi communists, party documents and additional interview evidence from the documentary film, We Were Communists, this thesis examines the origins, evolution and transformation of the relationship between the LCP and the Shiʿa after Lebanese independence in 1943, until the end of the Lebanese Civil War in 1990. Utilising the concepts of identity and political mobilisation, this thesis develops a hybridised approach to the study of political identity that combines primordial with constructionist readings of identity. This acknowledges the presence of a repertoire of multiple and varied identities among any individual or group, and their potential for mobilisation. Rather than assuming the domineering influence of primordial sentiments, such as sectarian identity, the hybridised approach requires an analysis of the conditions under which a particular identity becomes the basis for political mobilisation. In the aftermath of Lebanese independence in 1943, the Shiʿi community’s political mobilisation was characterised by a politics of resistance. This was a product of the legacy of the Shiʿi community’s experience of the French Mandate (1920-1943), as well as the newly reformulated confessional political system that was established by the National Pact (1943). The net effect of these processes was the marginalisation of the Shiʿa. The LCP, as a prominent anti-system opposition movement in Lebanon at this time, became the Shiʿi community’s main vehicle for the mobilisation and development of their resistance identity. During the Lebanese Civil War (1975-1990) the relationship between communism and the Shiʿa transformed as the LCP went into decline and new Shiʿi political actors emerged. The mantle of the Shiʿi community’s resistance identity became subject to the tensions between communism and communalism within the community. In the end, the Shiʿi community’s resistance identity was adopted and repackaged by Hizbullah, under whose auspices it remains today. The Shiʿi-communist relationship constitutes the Shiʿi community’s first engagement with formal, party-based and ideologically driven political mobilisation in Lebanon. The impact and legacy of the LCP’s influence on the Shiʿa in these terms encompasses not just the communist Shiʿa, but every other political actor in the community. Concern over the growing influence of communism led directly to the political mobilisation of the previously quietist Shiʿi religious clerics. This outcome is represented by the arrival of Imam Musa al-Sadr to Lebanon in 1959 and his stated goal of combatting the influence of communism among the Shiʿa. This thesis is an important addendum to the current understanding of the origins of Shiʿi political mobilisation, which erroneously place Musa al-Sadr at the beginning of that process. This study’s emphasis on alternative, non-sectarian forms of political identity is also a reminder of the Shiʿi community’s political diversity at a time when critical voices, resentful of Hizbullah’s and Amal’s monopoly, are currently emerging from within the ShiʿI community.
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Kirkov, Kirko Dimitar. "Tearing resistance for fillet welds in ships exposed to grounding : a full scale test & cost implications." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/11671.
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Sommer, Stacy Ann. "Siloxane-Polyurethane Fouling-Release Coatings Based On PDMS Macromers." Diss., North Dakota State University, 2011. https://hdl.handle.net/10365/29313.
Full textAbstract:
Marine biofouling is the accumulation of organisms onto surfaces immersed
in sea water. Fouling of ships causes an increase in hydrodynamic drag which
leads to performance issues such as increased fuel consumption and a reduced
top operating speed. Fouling-release (FR) coatings are one way that paints have
been used in combating biofouling by allowing for the easy removal of settled
organisms. Traditional FR coatings are silicone elastomers which are soft, easily
damaged, and require a tie coat for adhesion to marine primers. Siloxanepolyurethane
FR coatings have shown promise as FR coatings, providing
enhanced durability and toughness, better adhesion to marine primers, and
comparable FR performance to commercial coatings. Preliminary studies were conducted to explore the use of PDMS macromers
in the preparation of siloxane-polyurethane FR coatings. Attachment and removal
of fouling organisms on the siloxane-polyurethane coatings based on PDMS
macromers was comparable to commercial FR coatings. Extended water aging
was also carried out to determine effects of extended water immersion on the
fouling-release performance of the coatings. At up to four weeks of aging, the FR
performance of the coatings was not affected. Static immersion marine field testing was performed to determine the
fouling-release performance of siloxane-polyurethane coatings prepared with
PDMS macromers. The performance was found to be comparable to commercial FR coatings for up to one year, including water jet removal of slimes, barnacle
push-off removal, and soft sponging. The coatings showed good fouling-release
performance until extremely heavy fouling was allowed to settle.
Underwater hull cleaning was conducted for one siloxane-polyurethane
composition identified as a top performer from static field testing. The coating was
easily cleaned of fouling with rotating brushes for six months. The cleaning
capability of the coating was reduced when large barnacles and other extremely
heavy fouling was present. A commercial FR coating became heavily damaged
with brush cleaning while the siloxane-polyurethane coating remained mostly
undamaged. With more frequent cleaning, it is suspected that siloxanepolyurethane
coatings would show cleaning capability for longer periods of time.
Pigmentation of siloxane-polyurethane coatings based on difunctional
PDMS and PDMS macromers was explored to investigate the effect on FR
performance. Pigmentation with titanium dioxide caused a slight decrease in FR
performance in some cases, but this was easily overcome by the addition of
slightly more PDMS in the coating binder, thus illustrating the feasibility of
siloxane-polyurethane coatings as effective, pigmented FR coatings.
Finally, the exploration of unique PDMS polymer architectures has been
explored for the development of additional, novel, fouling-release coatings. The
incorporation of end-functional PDMS homopolymer molecular brushes and
branched PDMS macromers into siloxane-polyurethane fouling-release coatings
shows promise for the development of unique coatings where improved FR
performance may be obtained.Office of Naval Research (U.S.)
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Xing, Zhiliang. "Identification of the variance of the wave exciting rolling moment using ship's random response /." Internet access available to MUN users only, 2003. http://collections.mun.ca/u?/theses,170296.
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Bracco, Mark Douglas. "A study of the wedge cutting force through longitudinally stiffened plates : an application to grounding resistance of single and double hull ships." Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/26279.
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Pisil, Yalcin. "The Study on Neutralization of Human Immunodeficiency Virus and SARS CoV-2 - Neutralization Resistance of SHIV and Neutralization Assay for SARS CoV-2 -." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/264673.
Full textAbstract:
京都大学新制・課程博士
博士(人間・環境学)
甲第23392号
人博第1005号
新制||人||237(附属図書館)
京都大学大学院人間・環境学研究科相関環境学専攻
(主査)准教授 三浦 智行, 教授 川本 卓男, 准教授 西川 完途
学位規則第4条第1項該当
Doctor of Human and Environmental Studies
Kyoto University
DFAM
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Dudley, Dawn M. "HIV-1 ENV: IMPACTING HIV-1 FITNESS, ENTRY INHIBITOR DRUG SENSITIVITY, AND IN VIVO SELECTION OF A RESISTANT VIRUS TO THE MICROBICIDE PSC-RANTES." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1186757280.
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