Дисертації з теми "Ship seakeeping"
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1
Claudel, Remi. "Seakeeping enhancement bylengthening a ship." Thesis, KTH, Marina system, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-234835.
Анотація:
In this study, a tentative assessment of a passive solution for pitch decrease, namely the increase in length of the studied ship, is made. The hull form of the lengthened version of the ship is derived from the reference hull form after utilization of Lackenby’s sectional area curve transformation through a prismatic coefficient change (Reference [3]), and utilization of a sectional area curve “swinging” induced by a change of longitudinal position of the centre of buoyancy. Following this, and after a complementary mass estimate of the lengthened version, seakeeping calculations are made and show a significant decrease in pitch, from almost 35% for low sea states to 20% for relatively high sea states. To conclude this study, operability for classic NATO frigate missions have been calculated and the decrease in pitch induces a slight gain in operability for the lengthened version.
2
Johnson, Michael Charles. "Improvements in the conduct and interpretation of ship seakeeping trials." Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409610.
3
Xing-Kaeding, Yan. "Unified approach to ship seakeeping and maneuvering by a RANSE method." Hamburg Arbeitsbereiche Schiffbau, Techn. Univ. Hamburg-Harburg, 2006. http://doku.b.tu-harburg.de/volltexte/2006/303/.
4
Okan, Orhan Barbaros. "A design procedure for seakeeping analysis of close proximity ship towing." Thesis, Monterey, Calif. Naval Postgraduate School, 2002. http://hdl.handle.net/10945/6039.
Анотація:
Approved for Public Release; Distribution is Unlimited.The purpose of this thesis is to develop an efficient analysis and design procedure for assessing the seakeeping behavior of surface ships in close proximity towing. The problem is formulated by using the heave and pitch equations of motion in regular waves. The vertical plane relative motions between the trailing and the leading ships are matched through the speed-resistance characteristics of the trailing ship. A sea state degradation factor is introduced. This factor characterizes the expected seakeeping performance penalty resulting from the connection. A series of parametric studies is conducted for various geometric properties and environmental characteristics. The results can be used to evaluate the response of the system and provide insight into parameter selection for motion minimization.
5
Li, Lin. "Numerical seakeeping predictions of shallow water effect on two ship interactions in waves." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ63481.pdf.
6
Rudko, David D. "Logistical analysis of the littoral combat ship." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Mar%5FRudko.pdf.
Анотація:
Thesis (M.S. in Operations Research.)--Naval Postgraduate School, March 2003.Thesis advisor(s): David A. Schrady, Kevin J. Maher. Includes bibliographical references (p. 71-74). Also available online.
7
Xing-Kaeding, Yan [Verfasser]. "Unified approach to ship seakeeping and maneuvering by a RANSE method / von Yan Xing-Kaeding." Hamburg : Arbeitsbereiche Schiffbau, Techn. Univ. Hamburg-Harburg, 2006. http://d-nb.info/980303303/34.
8
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.
Анотація:
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.
9
Mousaviraad, Sayyed Maysam. "CFD prediction of ship response to extreme winds and/or waves." Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/559.
Анотація:
The effects of winds and/or waves on ship motions, forces, moments, maneuverability and controllability are investigated with URANS computations.
The air/water flow computations employ a semi-coupled approach in which water is not affected by air, but air is computed assuming the free surface as a moving immersed boundary. The exact potential solution of waves/wind problem is modified introducing a logarithmic blending in air, and imposed as boundary and initial conditions. The turbulent air flows over 2D water waves are studied to investigate the effects of waves on incoming wind flow. Ship airwake computations are performed with different wind speeds and directions for static drift and dynamic PMM in calm water, pitch and heave in regular waves, and 6DOF motions in irregular waves simulating hurricane CAMILLE. Ship airwake analyses show that the vortical structures evolve due to ship motions and affect the ship dynamics significantly. Strong hurricane head and following winds affect up to 28% the resistance and 7% the motions. Beam winds have most significant effects causing considerable roll motion and drift forces, affecting the controllability of the ship.
A harmonic wave group single run seakeeping procedure is developed, validated and compared with regular wave and transient wave group procedures. The regular wave procedure requires multiple runs, whereas single run procedures obtain the RAOs for a range of frequencies at a fixed speed, assuming linear ship response. The transient wave group procedure provides continuous RAOs, while the harmonic wave group procedure obtains discrete transfer functions, but without focusing. Verification and validation studies are performed for transient wave group procedure. Validation is achieved at the average interval of 9.54 (%D). Comparisons of the procedures show that harmonic wave group is the most efficient, saving 75.8% on the computational cost compared to regular wave procedure. Error values from all procedures are similar at 4 (%D). Harmonic wave group procedure is validated for a wide range of Froude numbers, with satisfactory results.
Deterministic wave groups are used for three sisters rogue waves modeling. A 6DOF ship simulation is demonstrated which shows total loss of controllability with extreme ship motions, accelerations and structural loads.
10
Bassler, Christopher Colby. "Analysis and Modeling of Hydrodynamic Components for Ship Roll Motion in Heavy Weather." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/23258.
Анотація:
Ship roll motion has been the subject of many studies, because of the complexities associated with this mode of ship motion, and its impact on operability, safety, and survivability. Estimation and prediction of the energy transfer and dissipation of the hydrodynamic components, added inertia and damping, is essential to accurately describe the roll motions of a ship. This is especially true for ship operations in moderate to extreme sea conditions. In these conditions, a complex process of energy transfer occurs, which alters the physical behavior of the hydrodynamic components, and ultimately affects the amplitude of ship roll motion. Bilge keels have been used on ships for nearly two centuries, to increase damping and reduce the severity of roll motions experienced by a ship in waves. Because ship motions are more severe in extreme sea conditions, large roll angles may occur. With the possibility of crew injury, cargo damage, or even capsize, it is important to understand the behavior of the roll added inertia and damping for these conditions. Dead ship conditions, where ships may experience excitation from beam, or near beam, seas present a worst case scenario in heavy weather. The behavior of a ship in this condition should be considered in both the design and assessment of seakeeping performance.
In this study, hydrodynamic component models of roll added inertia and roll damping were examined and assessed to be unsuitable for accurate prediction of ship motions in heavy weather. A series of model experiments and numerical studies were carried out and analyzed to provide improved understanding of the essential physical phenomena which affect the hydrodynamic components and occur during large amplitude roll motion. These observations served to confirm the hypothesis that the existing models for roll added inertia and damping in large amplitude motions are not sufficient. The change in added inertia and damping behavior for large roll motion is largely due to the effects of hull form geometry, including the bilge keels and topside geometry, and their interactions with the free surface. Therefore, the changes in added inertia and damping must be considered in models to describe and predict roll motions in severe wave environments.
Based on the observations and analysis from both experimental and numerical methods, several time-domain model formulations were proposed and examined to model hydrodynamic components of large amplitude roll motions. These time-domain formulations included an analytical model with memory effects, a piecewise formulation, and several possibilities for a bilge keel force model. Although a piecewise model for roll damping was proposed, which can improve the applicability of traditional formulations for roll damping to heavy weather conditions, a further attempt was undertaken to develop a more detailed model specifically for the bilge keel force. This model was based on the consideration of large amplitude effects on the hydrodynamic components of the bilge keel force. Both the piecewise and bilge keel force models have the possibility to enable improved accuracy of potential flow-based numerical prediction of ship roll motion in heavy weather. However, additional development remains to address issues for further practical implementation.
Ph. D.
11
Bigi, Nedeleg. "Investigation of the dynamic motions and operability of a ship towed by kite." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0133/document.
Анотація:
Afin de réduire les émissions de gaz à effet de serre et le coût du transport maritime, l'utilisation des cerfs-volants comme système de propulsion auxiliaire des navires est prometteuse. Pour estimer les performances et l’opérabilité d’un navire tracté par cerf-volant, une modélisation dynamique du système est alors mise en oeuvre. Une modélisation analytique de cerf-volant est utilisée. Ce modèle néglige la masse du cerf-volant et suppose que les lignes sont droites et indéformables. Ces hypothèses conduisent à un modèle cinématique dépendant du coefficient de portance et de la finesse aérodynamique. Une évolution linéaire des coefficients aérodynamiques en fonction de la courbure de la trajectoire de vol est proposée. Par ailleurs, en développant un modèle quasi analytique de ligne, il est montré qu’à partir de 2 m.s-1 de vent relatif que l’hypothèse de ligne droite est raisonnable. En se basant sur un modèle de ligne, un critère analytique de vitesse de vent minimum permettant un vol quasi-statique est présenté. Dans le but de résoudre l’ensemble des termes d’interaction entre le cerf-volant et le navire, un modèle linéarisé de tenue à la mer temporelle est développé. Le produit de convolution de la réponse impulsionnelle du navire est calculé avec des systèmes d’états. Cependant comme celle-ci représente mal les mouvements horizontaux des navires, le modèle développé est alors couplé à un modèle de manoeuvrabilité. Pour étudier les interactions entre le cerf-volant et le navire un couplage monolithique et un couplage dissocié sont comparés. Le couplage dissocié néglige l’influence des mouvements du navire sur le vol du cerf-volant. En cas de mer calme, les résultats obtenus par les deux types de couplage sont très proches. En cas de houle régulière les mouvements du navire sont principalement causés par la houle. Le couplage monolithique montre qu’un réseau de sous-harmoniques basse fréquence apparait alors dans le spectre d’excitation du navire. La fréquence fondamentale des sous-harmoniques est donnée par la différence entre la fréquence de vague et la fréquence de l’harmonique la plus proche de l’excitation du kite. Quand cette différence est suffisamment petite, un phénomène d’accrochage apparait. Ce phénomène est bénéfique pour le cerf-volant et le navire quand le décalage des harmoniques d'excitation correspond à une augmentation. Par ailleurs, une étude de la stabilité de route montre qu'il est nécessaire de contrôler activement le safranIn order to reduce greenhouse gas emissions and shipping costs, the use of kites as an auxiliary propulsion device for ships is promising. In order to estimate the performance and the operability of a kite-towed vessel, a dynamic modeling of the system is implemented. A classical kite modeling is used. This model neglects the mass of the kite and assumes straight and inelastic tethers. These assumptions lead to a kinematic model depending on the lift coefficient and the aerodynamic lift to drag ration angle. A linear evolution of these aerodynamic coefficients as a function of the curvature of the flight path is proposed. In addition, by developing a quasi-analytical line model, it is shown that from 2 m.s-1 of relative wind the straight tether assumption is reasonable. Based on the tether model, an analytical criterion assessing the minimum wind speed to enable a quasi-static kite flight is developed. To solve all the interaction terms between the kite and the ship, a time domain seakeeping model based on the linearized ship equation of motion assuming a potential flow is developed. The convolution product of the impulse response of the ship is computed with state-space systems. However, since horizontal ship motions are not well represented by such theories, a coupling with a maneuvering model is presented.Comparisons to experimental data tests show good agreements. To study the interactions between the kite and the ship, a monolithic coupling and a dissociated coupling are compared. The dissociated coupling neglects the influence of ship motions on the kite flight. In a calm water case, results obtained by the two types of coupling are very close. In regular waves, ship motions are dominated by the wave influence. Thus, with the monolithic coupling, a network of low frequency subharmonic appears in the kite excitation spectrum. The fundamental frequency of the subharmonic is given by the difference between the wave frequency and the frequency of the nearest kite excitation harmonic. When this difference is small enough, a lock-in phenomenon appears. This phenomenon is a benefit for the kite and the ship when the shift of the excitation harmonics corresponds to an increase. Furthermore, a course keeping stability study shows that the rudder needs to be actively controlled
12
Rollings, Sarah E. "Seakeeping analysis of small displacement high-speed vessels." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Mar%5FRollings.pdf.
13
Kurultay, Aziz Alper. "Sensitivity analysis of the seakeeping behavior of trimaran ships." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Dec%5FKurultay.pdf.
14
Rollings, Sarah E. "Rudko, David D.:." Thesis, Monterey, California. Naval Postgraduate School, 2003.
Анотація:
In developing designs for high speed vessels, the engineer must account for the response of the ship in the environment while operating at mission essential speeds. This thesis presents a seakeeping analysis of David Taylor Model Basin's Series 64 models scaled to a 2500-ton displacement using the SHIPMO and MATLAB software. It also discusses the current technology associated with high speed vessels (HSV's) and the relation to the US Navy. Series 64 models provided the benchmark for resistance data. To expand upon this well known series, this research develops seakeeping data trends for scaled-up models. SHIPMO allows the user to specify the ship's characteristics and the environmental conditions such as wave specifications and spectrum. Using the output files from SHIPMO, the MATLAB program designed during this thesis, produced contour plots for the models' response in pitch and heave. Seakeeping trends were observed based on the plots and further compared to calculations of the seakeeping rank, R, a formula originally developed by Nathan Bales. The results of the research can be used by engineers in application to the design of small displacement, high speed ships, both monohulls and multi-hulls.http://hdl.handle.net/10945/1070
US Navy (USN) author.
15
Milandri, Giovanni Sergio. "Seakeeping control of HYSUCATs." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/2993.
Анотація:
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2006.This thesis investigates practical methods of modelling and control of the vertical motions of a hydrofoil assisted catamaran, the HYSUCAT. The aim of the control application is to reduce the motions, and consequently the motion sickness of the passengers. First, a potential flowcommercial program, POWERSEA,was used to model the system. This uses 2-D strip methods to model the planing hull-form of the vessel, and the Peter du Cane hydrofoil theory for modelling of the foils. These simulations are compared to experimental towing tank results, with fair agreement at lower speeds, but limited applicability at high speeds. Thus for the control design the agreement was insufficient. As an alternative, a simple coupled 2 degree-of-freedom spring - mass - damper model is proposed, for which the equations of motion are derived. This has 9 unknown parameters; three of these aremeasured directly, two are modelled, and the remaining four were identified using an experimental parameter estimation technique. Representative parameter values were calculated frommultiple experiments for application in the control design. The design of a control system was based on the above model. First, an output-weighted Linear Quadratic Regulator (LQR) was designed to obtain the full state feedback gains. A non-linear ’bang-bang’ control design was then implemented to try and speed up the response of the system. These control strategies, as well as no control, were applied in the towing tank in regular waves, with good results at low and medium frequencies. At the design point, 32% and 65% reductions in rms motions were achieved for pitch and heave, respectively. At high frequencies, though, not much improvement was achieved due to the bandwidth limitation of the control system. The LQR results were better overall (reduced motions) across the frequency range than the bang-bang controller, as well as having a lower added resistance in waves. The control design of the output-weighted LQR was then revised to be based on alternative outputs, as a possible improvement. However, a further two controller designs did not yield any noticeable improvement and were not developed further.
16
Zhou, Zhengquan. "A theory and analysis of planing catamarans in calm and rough water." ScholarWorks@UNO, 2003. http://louisdl.louislibraries.org/u?/NOD,45.
Анотація:
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.
17
Vanden, Berg Scott M. "Non-linear rolling of ships in large sea waves." Thesis, Monterey, California. Naval Postgraduate School, 2007. http://hdl.handle.net/10945/3003.
Анотація:
CIVINSThe United States Navy has taken a new interest in tumblehome hulls. While the stealth characteristics of these hull forms make them attractive to the Navy, their sea keeping characteristics have proven to be problematic. Normal approximations of sea keeping characteristics using linear differential equations with constant coefficients predict a very stable platform, while observations in model tests show a ship that is prone to extreme roll transients. This thesis examines a simple method of producing a non-linear simulation of roll motion using a tumblehome hull provided by the Office of Naval Research. This research demonstrates the significant difference that a variable restoring coefficient introduces into a hull's seakeeping characteristics.
Contract number: N62271-97-G-0026
CIVINS
18
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.
Анотація:
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
19
Kopke, Markus. "A passive suspension system for a hydrofoil supported catamaran." Thesis, Stellenbosch : University of Stellenbosch, 2008. http://hdl.handle.net/10019.1/1991.
Анотація:
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2008.This study investigates practical passive methods to improve the seakeeping of a Hydrofoil Supported Catamaran (Hysucat). The Hysucat is a hybrid vessel combining hydrofoil efficiency with the stability of catamarans. The seakeeping of the Hysucat was initially investigated experimentally to determine what seakeeping improvements are inherent to the Hysucat design. The results showed that the seakeeping is improved by 5-30%. A passive suspension system for the main hydrofoil of the Hysucat was designed and tested. A concept development strategy was followed for the design of the suspension system as such a system had never been investigated previously. Detailed specifications for the design were developed and concepts that could satisfy the customer and engineering requirements were generated. Numerical simulation models for the Hysucat and the final concepts were derived assuming a simplified 2nd order system to describe the seakeeping dynamics of the demi-hulls. Unknown parameters were determined using parameter estimation techniques. Representative parameter values were calculated from multiple towing tank experiments. Theory describing the motion of a hydrofoil in an orbital velocity wave field was combined with the hull model to simulate the Hysucat as well as the suspension system concepts. The models indicated that the concept where the main hydrofoil was attached to a spring loaded arm, that was free to pivot in response to orbital waves, was the most feasible in damping out vertical transmitted accelerations. Experimental tests indicated that little improvement was achieved with the suspension system at low frequencies. At resonance the suspension system was effective in decreasing the heave of the vessel by up to 27%. The pitch and acceleration response results showed improvements at the higher encounter frequencies of up to 50%. The calm water resistance of the vessel increased by 10% over the Hysucat with rigidly attached hydrofoils; however was still 24% less than the hull without foils.
20
Muñoz, Jaime Miguel Mariano Saldarriaga. "Estudo de uma metodologia para o dimensionamento de um tanque de provas do tipo reboque." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3135/tde-01032011-113219/.
Анотація:
Um tanque de provas do tipo reboque permite a realização de ensaios hidrodinâmicos com modelos em escala, sua presença é importante devido à possibilidade de obter características hidrodinâmicas que dimensionam a potência e qualidade do comportamento dos navios durante a sua operação, otimizando os projetos de forma particular ou geral, tanto para a navegação marítima, lacustre ou fluvial. O objetivo principal desta pesquisa é estudar e propor uma metodologia para o dimensionamento e concepção de um tanque de reboque para o Serviço Industrial da Marinha (SIMA PERU), principal estaleiro do Peru, de maneira que possa realizar os ensaios hidrodinâmicos correspondentes aos diferentes tipos de embarcações produzidas pelo SIMA PERU. Como propósito de estudo será desenvolvido uma análise de um tanque de reboque que permitirá ensaiar modelos de diferentes tipos de embarcações, levando em consideração as diferentes condições ambientais e climáticas relacionadas ao litoral peruano em toda sua extensão, isto é, uma condição marítima equivalente a uma escala Beaufort 5. Estas são as condições que foram requeridas para atuar na costa peruana. Será proposto um tanque de reboque com características próprias, baseado no razoável dimensionamento dos modelos reduzidos e nas necessidades e requerimentos de ensaio de acordo às recomendações apresentadas pela Conferência Internacional de Tanques de Reboque (International Towing Tank Conference- ITTC).A towing tank allows hydrodynamic testing with scale models, their presence is important because allows to obtain hydrodynamics characteristics that they measure the power and quality of behavior during the operation, optimizing the designs in general or particular form of vessels for sea, lake or river. The main objective of this research is to study and propose a method for sizing and development of a towing tank for the Naval Industrial Service; SIMA - PERU, main shipyard from Peru, so it carry out hydrodynamics tests corresponding to different types of vessels produced by SIMA - PERU. The purpose of study will be developed analysis of a towing tank that will test models of different types of vessels, taking into account the different environmental and climatic conditions related to the Peruvian coast, in other words, sea conditions equivalent to a Beaufort \"5\". These are the conditions that were required to act on the Peruvian coast. Will be offered a towing tank with its own characteristics, needs and requirements based on the consistent sizing of reduced models and according to the recommendations made by the International Towing Tank Conference - ITTC.
21
Hou-YuLin and 林后鈺. "The Development of the Ship Weather Routing Planning Based on the Ship Seakeeping Characteristics." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/07417859061882364040.
Анотація:
碩士國立成功大學
系統及船舶機電工程學系碩博士班
100
Abstract The rising fuel price and the greenhouse effect on the environment gradually become serious problems. Reducing fuel consumption will be an very important issue in sailing. Over the past decade, the world's major shipbuilding and shipping companies, such as Samsung Heavy Industries, Kawasaki Heavy Industries and Global Shipbuilding, etc., applied the concept of weather routing to develop navigation support systems to improve energy efficiency, safety of cargos, ships and ship crew. This thesis creates an analytical software including the ship seakeeping characteristics to extend the concept. In the present study the ship motion response characteristics calculated in the form of Response Amplitude Operator (RAO) and combine the ISSC spectrum to establish the database which includes the significant motion and mean added resistance. In the simulation, the database can offer several optional solutions of safe route planning with respect to the real-time weather information in every waypoint and the optimal route can be finally suggested. Optimization models are constructed for deterministic minima with respect to the distance and the fuel consideration. An container ship is selected as the calculation model and realistic solutions for the ship routing planning are obtained based on real-time weather information from NOAA’s forecast. Several algorithms are used in this thesis and different comparisons of fuel-efficiency are already made. Some conclusions of the limitations of the prediction models are also made according to the present results.
22
Chun-ChangChou and 周群璋. "The Effect of Different Ship Sailing Attitude on Seakeeping Performance." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/14486568960374173703.
Анотація:
碩士國立成功大學
系統及船舶機電工程學系
103
This research aims at figuring out the effect of different draft and trim angle of the ships on seakeeping performance by well-developed computer simulation program for ship hydrodynamics. In the research, three different types of ships are to be compared. They are tanker ship, container ship, and bulk carrier ship (series 60), which all have different value of block coefficient (CB). The existing computer program based on strip theory is applied to calculate the ship motions and added resistance. Experimental tests are carried out to verify the results from the computer program. However, the tests only include longitudinal waves conditions due to the limitation of the facilities in NCKU Towing Tank. The experimental test also includes the measurement of moment of inertia for pitch motion of whole ship model. From the results, we found that for container ship, sailing attitudes with trim by stern show good performance in heave motion, pitch motion, and added resistance generally. However, for roll motion, trim by bow 1° status shows the best performance. For tanker ship, sailing attitudes with trim by stern also show good performance in heave motion, pitch motion, and added resistance generally. However, for roll motion, even keel status shows the best performance. For series 60 ship, sailing attitude with trim by stern also has good performance in heave motion, pitch motion, and added resistance. However, trim by stern status has the worst performance in roll motion among all the sailing attitudes. Generally speaking, for series 60 ship, there is no best sailing attitude adapted to all conditions, because each sailing attitude has different advantages and drawbacks of seakeeping performance.
23
Rixmann, D. Bradley. "Time domain seakeeping simulations of some multiple waterplane vessels /." 2001.
24
Yang, Jyh-Cherng, and 楊志成. "A Study on the Ships' Seakeeping of R.O.C. Coast Guard." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/92173548157982121131.
Анотація:
碩士國立臺灣海洋大學
商船學系所
98
Coast Guard Administration is the maritime law-enforcement agency, which executes the patrolling mission of the territorial waters and the economic zone and saving projects under a harsh climate. The administration is equipped by large, medium and small patrol vessels. The vessels which are over 500 tonnages enable to be on duty overseas while the Beaufort wind scale is over 9. Those vessels assigned by the Council of Agriculture and the Bureau of Customs and the ones made itself undertake the duty of the maritime law enforcement. The seakeeping of the vessels is related to their size and length. Obviously, the seakeeping of the large vessels is better than the small ones. Among the similar vessels, the difference of the seakeeping exists. The stability of the vessels is the main factor of the seakeeping. It depends on the roll amplitudes and the acceleration. The former has influences on the sailors’ exercise capacity, and the latter causes seasickness and the damage of the equipments and the construction. Therefore, if the seakeeping criterion of exercise casting boats, salvaging operation, towing operation, and fire-fighting operation can be established, it will make the rules for the sailors, procedures and equipments to follow. Furthermore, it makes sure of the safety of the vessels. The purpose of the present study is to investigate the ability of searching and rescuing of the vessels, the stability of the vessels, the seakeeping and the roll amplitudes, and the seakeeping and the wave. According to the investigation, the researcher investigates the vessel composition, the stability, the seakeeping and the operations. The researcher will analyze the data and confer the possible problem by means of the questionnaires. The study will be presented for the reference of the execution of the vessels and the construction of the vessels. The conclusion of this study is to provide a method for the administration to develop the ability of searching and rescuing, evaluate the executing situation, establish the criterion of the seakeeping, develop the seakeeping, and build the statistics of the sea states. Therefore, it can help to keep the vessels, staffs, and the equipments safe.
25
Holloway, Damien Scott. "A high Froude number time domain strip theory applied to the seakeeping of semi-SWATHs /." 1998. http://adt.lib.utas.edu.au/public/adt-TU20060504.153413.
26
Bandas, John. "Seakeeping for the T-Craft Using Linear Potential and Nonlinear Dynamic Methods." Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11083.
Анотація:
A system of ordinary differential equations (ODE) is constructed for an air cushion vehicle (ACV). The system is simplified to an equation for the balance of the vertical forces and the equation for the adiabatic compression of the air in the cushion. Air pressure is constantly supplied into the system, but can leak out from underneath the edges of the cushion. A series of regular waves encounters the air cushion, causing a change in volume.
Additionally, a computational analysis of the seakeeping of a Surface Effect Ship (SES) is performed using the commercial software WAMIT, which uses low-order, linear potential panel method. The model of the T-Craft consists of catamaran hulls, rigid end skirts, and the interface between the air cushion and the water surface. Beyond the six rigid body degrees of freedom of the T-Craft, additional modes are added for the motion of the interface panels. To verify the method used, the model is benchmarked using computational data for a small-scale barge model and experimental data for a T-Craft model. A comparison is performed for the T-Craft with and without its cushion.
The solution for the nonlinear time-domain system is found numerically, and the stability of the system is studied by observing bifurcations with the incoming wave amplitude as the bifurcation parameter. The system experiences a period-doubling bifurcation, from a periodic orbit, to a subharmonic orbit, to a solution with multiple periods. Further increasing the wave amplitude increases the period doubling, eventually leading to chaotic behavior.
As a result of the linear-potential simulations, significant differences are found in the seakeeping of the T-Craft when on and off the cushion. These differences are caused by the direct and indirect effects of the cushion (added aerodynamics and a decreased draft). The RAO's of the craft experience changes in amplitude and phase, which will affect the multi-body relative motions. The time-domain model shows very chaotic behaviour that is presented visually in a bifurcation diagram. These linear potential and time-domain methods illustrate the complexity and importance of modelling air-cushion effects.