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Journal articles on the topic 'Ship resistance'
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1
He, Ngo Van, Keisuke Mizutani, and Yoshiho Ikeda. "REDUCING AIR RESISTANCE ACTING ON A SHIP BY USING INTERACTION EFFECTS BETWEEN THE HULL AND ACCOMMODATION." ASEAN Engineering Journal 7, no. 1 (December 26, 2014): 1–14. http://dx.doi.org/10.11113/aej.v7.15484.
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Nowaday, a study on saving energy as well as reducing resistance acting on a ship is important in maritime transportation. In this study, the authors present a study on reducing air resistance acting on a ship by using interaction effects between the hull and an accommodation. At first, air resistances acting on a hull and an accommodation of the ship are investigated by a commercial Computation Fluid Dynamic (CFD) code. Then, CFD results are compared with those of experimental results to validate the accuracy of the CFD. Secondly, air resistances acting on the ship with an accommodation on its deck are computed to obtain air resistances acting on the whole ships, on the hull and on accommodation. The results demonstrate that the interaction effects between the hull and its accommodation house be also shown how to reduce the total air resistance by using interaction effects between the hull and an accommodation house. The results can be applied in reducing the total resistances acting on a ship.
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Yang, Yunfei, Zhicheng Zhang, Jiapeng Zhao, Bin Zhang, Lei Zhang, Qi Hu, and Jianglong Sun. "Research on Ship Resistance Prediction Using Machine Learning with Different Samples." Journal of Marine Science and Engineering 12, no. 4 (March 26, 2024): 556. http://dx.doi.org/10.3390/jmse12040556.
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Resistance serves as a critical performance metric for ships. Swift and accurate resistance prediction can enhance ship design efficiency. Currently, methods for determining ship resistance encompass model tests, estimation techniques, and computational fluid dynamics (CFDs) simulations. There is a need to improve the prediction speed or accuracy of these methods. Machine learning is gradually emerging as a method applied in the field of ship research. This study aims to investigate ship resistance prediction methods utilizing machine learning across various datasets. This study proposes two methods: employing stacking ensemble learning to enhance resistance prediction accuracy with identical ship samples and utilizing various ship resistance prediction models for accurate resistance prediction through transfer learning. Initially focusing on container ships as the research subject, the stacking ensemble learning model outperforms the basic machine learning model, the Holtrop and Mennen method, and the updated Guldhammer and Harvald method based on comparative prediction results. Subsequently, the container ship resistance prediction model achieves precise resistance prediction for bulk carriers. This study offers dependable guidance for applying machine learning in predicting ship hydrodynamic performance.
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Gutiérrez-Romero, José Enrique, and Jerónimo Esteve-Pérez. "Assessment of the Influence of Added Resistance on Ship Pollutant Emissions and Freight Throughput Using High-Fidelity Numerical Tools." Journal of Marine Science and Engineering 10, no. 1 (January 10, 2022): 88. http://dx.doi.org/10.3390/jmse10010088.
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The reduction of ship pollutants is a key issue in the international agenda. Emissions estimation is usually based on standard calculations that consider the different scenarios of ships. This work presents research on the influence of added resistance on ship emissions and freight throughput. First, a methodology to assess the added resistance influence is shown. The procedure is applied to a roll on-roll off ship under two load conditions. Analyses are computed to value wind- and wave-added resistances for different seasons. An investigation on ship pollutant emissions for a whole route is performed. Moreover, the influence of added resistance on the ship freight throughput is analyzed. Finally, some relevant information is concluded. For instance, a difference of up to 53% in pollutant emission estimation is observed if added resistance is considered. Additionally, the navigation in added resistance conditions could lead to a freight loss of 18% per operational year.
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Huang, Jiayu, Feng Diao, Shifeng Ding, Sen Han, Pentti Kujala, and Li Zhou. "A Study on the Ice Resistance Characteristics of Ships in Rafted Ice Based on the Circumferential Crack Method." Water 16, no. 6 (March 15, 2024): 854. http://dx.doi.org/10.3390/w16060854.
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In previous studies of ship–ice interactions, most studies focused on ship–level ice interactions, overlooking potential rafted ice conditions in extreme ice conditions. The purpose of this study is to develop a numerical model for predicting ship resistance in rafted ice regions. Numerical modeling of rafted ice was carried out using preset grid cells. By comparing the model test results, the accuracy and reliability of the numerical model are verified. On this basis, we undertook the analysis of the impacts of different ice thicknesses, ship speeds, bending strengths, and crushing strengths on the ice resistance of ships under level and rafted ice conditions. The results show that the ice resistance of ships is significantly higher than that of rafted ice under the condition of level ice; however, level ice and rafted ice have different effects on ship ice resistance. Compared with level ice, the ice resistance of ships navigating in rafted ice is more concentrated. The findings of the present research can serve as a technical reference for studies focused on predicting ship resistance in rafted ice regions.
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Ismail, Izzuddin Nadzir, Parlindungan Manik, and Mahendra Indiaryanto. "Effect of the Addition of Hydrofoil on Lift Force and Resistance in 60 M High-Speed Vessel." Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan 17, no. 3 (October 1, 2020): 95–106. http://dx.doi.org/10.14710/kapal.v17i3.28772.
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The development of sea transportation technology is needed to meet the demand for ships that can carry heavier loads and operate at high speeds. Modifications in the form of additional hydrofoil variations were conducted to produce higher lift and reduce the resistance generated by the ship so that the ship can go more efficiently at high speed. This study aims to obtain the effect of adding hydrofoil to ships with variations in the type and shape of foil and find out which types and shapes can reduce resistance on the ship. This research was conducted with several model analysis tests using Computational Fluid Dynamic (CFD) based software, namely Tdyn, at several different speeds. The results of this study show that of the six variation models analyzed, rectangular fully submerged foil models can reduce the total resistance value of the ship by 17.822% from the original ship on Froude Number (Fr) 0.670. The type and shape of the foil is very influential on the lift and resistance produced by the ship.
6
Jin, Chenhao. "Review on the ship drag reduction technology." Theoretical and Natural Science 19, no. 1 (December 8, 2023): 275–80. http://dx.doi.org/10.54254/2753-8818/19/20230574.
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The development of the theory of turbulence has made a breakthrough in the application of drag reduction technology on ships, which contributes to energy saving and environmental protection. When a ship is sailing, it has to overcome resistance. Total resistance includes frictional resistance, wave-making resistance, and viscous pressure resistance, in which frictional resistance acts as the main resistance for low-speed ships, and for high-speed ships, the main resistance is wave-making resistance. This paper reviews the ship drag reduction technology by giving a brief introduction to drag reduction methods using grooves, bulbous bows, bubbles, hydrofoils, wall vibration, and high-polymer additive respectively, as well as their principles.
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Xie, Chang, Li Zhou, Mingfeng Lu, Shifeng Ding, and Xu Zhou. "Numerical Simulation Study on Ship–Ship Interference in Formation Navigation in Full-Scale Brash Ice Channels." Journal of Marine Science and Engineering 11, no. 7 (July 5, 2023): 1376. http://dx.doi.org/10.3390/jmse11071376.
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Formation navigation in brash ice channels is increasingly utilized by merchant vessels in the Arctic and Baltic Sea, offering benefits such as improved efficiency and reduced carbon emissions. However, ship–ship interference poses a significant challenge to this method, impacting resistance performance. This paper presents full-scale simulations using the CFD–DEM coupling method in brash ice channels, which is validated by comparing simulation results with ice tank measurements. By varying the distance between two ships from 0.05 to 5 ship lengths, ship–ship interference in full-scale brash ice channels is analyzed using the CFD–DEM coupling strategy. The study examines hydrodynamic and ship–ice interactions, ice resistance effects, and simulation results. It is found that ship-to-ship distance significantly influences the velocity field, dynamic pressure distribution on the hull, and hydrodynamic interaction forces. Distances less than one ship length result in increased water resistance for the forward ship and decreased resistance for the rear ship. The forward ship demonstrates favorable interference with the ice accumulation of the rear ship. When distances are less than two ship lengths, the ice resistance of the forward ship remains mostly unaffected, while the ice resistance of the rear ship decreases as the distance decreases. These insights enhance our understanding of ship–ship interference in formation navigation, aiding in the optimization of brash ice channel navigation strategies.
8
Xu, Xiao Ying, Chao Ying Meng, and Kuan Wang. "Resistance Performance Forecast of Trimaran Based on Multiple Regression Analysis." E3S Web of Conferences 261 (2021): 02072. http://dx.doi.org/10.1051/e3sconf/202126102072.
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Based on the multiple linear regression of the relevant data of 29 ships in the basic database, including cargo ship, oil ship, container ship and chemical ship, etc, the empirical estimation formula of resistance coefficient of single ship under different Fr was obtained. The feasibility of applying the above regression formula to the prediction of the resistance performance of the trimaran based on DTMB5415 is verified by comparison with CFD simulation data. This method has a strong engineering applicability and provides a new idea for the study of computer-aided layout optimization of the trimaran.
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Rachmianty, Andi, Suandar Baso, and Syamsul Asri. "The Influences of Lengthening Dimension of Ro-Ro Ferry Toward the Considerations of Hydrodynamics Characteristic and Loading Capacity Aspect." EPI International Journal of Engineering 2, no. 1 (June 27, 2019): 41–45. http://dx.doi.org/10.25042/epi-ije.022019.08.
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The ferry business has become an important business segment for ship designers, builders and operators. Therefore, many ways have been done in order to increase ferry business through the proper design or converting ships by lengthening. This research is focused on the influences of lengthening a Ro-Ro ferry to hydrodynamics characteristic and loading capacity aspects. Moreover, the ships also are fixed in the same width and draft dimensions. The difference of the Ro-Ro ferries length is indicated by the addition of one column of car space where one column car space is given by car size including distance between car columns spaces which is an increment of every 5.88 meter. The total resistances of Ro-Ro ferries are obtained by ship model experiment in towing tank. There are 4 ship models that are made. The lengthening a Ro-Ro ferry is described into non-dimensional parameter by the ratio of ship length and displacement volume (L/V1/3). The hydrodynamics and the loading capacity of carried car aspects could be described into the ratio of resistance and loading capacity of carried car (RT/SUK) with ship speed. The research result shows that the lengthening of a Ro-Ro ferry affects on total resistance, speed, and loading capacity of carried car. The increase of total resistance is caused by higher residual resistance at high speeds and this is experienced by small length size. Therefore by lengthening the Ro-Ro ferry it could reduce total resistance in the same speed especially the residuary resistance but eventhough lengthening Ro-Ro ferry the effective speed should be considered. In additions, the effective speed for actual ships dimension in the same Rt/SUK 0.05 i.e. B5L10 is about 13.85 knot, B5L11 14.33 knot, B5L12 14.94 knot, and B5L13 15.45 knot respectively.
10
Martić, Ivana, Nastia Degiuli, Andrea Farkas, and Ivan Gospić. "Evaluation of the Effect of Container Ship Characteristics on Added Resistance in Waves." Journal of Marine Science and Engineering 8, no. 9 (September 9, 2020): 696. http://dx.doi.org/10.3390/jmse8090696.
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Added resistance in waves is one of the main causes of an increase in required power when a ship operates in actual service conditions. The assessment of added resistance in waves is important from both an economic and environmental point of view, owing to increasingly stringent rules set by the International Maritime Organization (IMO) with the aim to reduce CO2 emission by ships. For that reason, it is desirable to evaluate the added resistance in waves already in the preliminary ship design stage both in regular and irregular waves. Ships are traditionally designed and optimized with respect to calm water conditions. Within this research, the effect of prismatic coefficient, longitudinal position of the centre of buoyancy, trim, pitch radius of gyration, and ship speed on added resistance is investigated for the KCS (Kriso Container Ship) container ship in regular head waves and for different sea states. The calculations are performed using the 3D panel method based on Kelvin type Green function. The results for short waves are corrected to adequately take into account the diffraction component. The obtained results provide an insight into the effect of variation of ship characteristics on added resistance in waves.
11
Liu, Zhengyuan, Changming Dai, Xiaohui Cui, Yu Wang, Hui Liu, and Bo Zhou. "Hydrodynamic Interactions between Ships in a Fleet." Journal of Marine Science and Engineering 12, no. 1 (December 26, 2023): 56. http://dx.doi.org/10.3390/jmse12010056.
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There has always been a concern about the hydrodynamic interaction between ships in a flow field. In this study, the RANS method is utilized, and the hydrodynamic interference between two KRISO Container Ships (KCS) operating in still water with identical parameters and sailing at the same speed is investigated. Overlapping grids are used to simulate ship motion, and the VOF method is used to simulate the free surface. A KCS ship model of 1:1 size without propeller is used in the study. In order to study the change principle of the Kelvin flow field created by a single ship, the resistance coefficient and the flow field surrounding the ship are first calculated for the monohull case. Then the influence of interference between two ships is examined at various speeds and intervals and compared with the monohull case. It is discovered that the resistance coefficient of the following ship is reduced in a certain speed interval under the influence of the leading ship, where the maximum reduction can be up to 24.3%. The reason for this phenomenon may be that the wave around the following ship is superimposed on the transverse wave behind the leading ship. When the height of the wave is suppressed, the following ship’s resistance is reduced.
12
Sugianto, Erik, Jeng-Horng Chen, Rohman Sugiono, and Hadi Prasutiyon. "Effect of portable conveyor placement in ship on ocean waste collection behavior." IOP Conference Series: Earth and Environmental Science 1095, no. 1 (October 1, 2022): 012015. http://dx.doi.org/10.1088/1755-1315/1095/1/012015.
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Abstract This study, the portable conveyor placement of ocean waste collection ships was numerically investigated by using computational fluid dynamics. Monohull ship models with different conveyor location variations are namely at the bow of the ship, on both sides of the ship, and on the bow and both sides of the ship. The three indicators used to assess ships in collecting ocean waste are flow patterns that indicate whether or not ocean waste is easy to get in closer to the conveyor, velocity contours that indicate whether or not ocean waste is approaching the conveyor fast, and ship resistance that affects fuel consumption. The results show that the conveyor on the bow model is the easiest to get the ocean waste closer to the conveyor. This model also produces the smallest ship resistance compared to other models. While the conveyor model on the bow and both sides is the fastest to make the waste approach the conveyor. This model also makes ocean waste that is not caught on the conveyor of the front ship can be caught by the conveyor on the side of the ship. However, this model produces the largest ship resistance compared to other models.
13
Seok, Jun, and Jong-Chun Park. "Comparative Study of Air Resistance with and without a Superstructure on a Container Ship Using Numerical Simulation." Journal of Marine Science and Engineering 8, no. 4 (April 9, 2020): 267. http://dx.doi.org/10.3390/jmse8040267.
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This study investigated the resistance performance of ships, using the air resistance correction method. In general, air resistance is calculated using an empirical formula rather than a direct calculation, as the effect of air resistance on the total resistance of ships is relatively smaller than that of water. However, for ships with large superstructures, such as container ships, LNG (liquefied natural gas) carriers, and car-ferries, the wind-induced effects might influence the air resistance acting on the superstructure, as well as cause attitude (trim and sinkage) changes of the ship. Therefore, this study performed numerical simulations to compare the total resistance, trim, and sinkage of an 8000 TEU-class container, ship with and without superstructures. The numerical simulation conditions were verified by comparing them with the study results of the KCS (KRISO Container Ship) hull form. In addition, the differences in the above values between the two cases were compared using the coefficients calculated by the empirical formula to identify the effects on the air resistance coefficient.
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Jie, Liu, Zhang Bao-Ji, and Xu Ning. "Research on Design Optimization of High-Speed Ship Bulbous Bow Based on Nelder-Mead Algorithm." Journal of Ship Production and Design 38, no. 01 (February 3, 2022): 28–38. http://dx.doi.org/10.5957/jspd.07190039.
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In order to reduce the wave-making resistance of ships, this paper proposes an optimization design method for bulbous bow form based on potential flow theory. In this paper, we restrict our interest to parametric deformation of the bow, at the same time constrain the displacement and the length of the ship. Based on Rankine source method, the wave-making resistances of DTMB5512 and ITTC Ship A-2 are calculated. For optimization, Sobol algorithm is selected to create sample space; based on it, we use Nelder–Mead algorithm to obtain the optimal hull form in the space. Additionally, we compare and analyze the hydrodynamic performance of the ship. The results show that the optimization design method reduces the wave-making resistance of DTMB5512 and ITTC Ship A-2, which verifies the feasibility of the method. Introduction Energy Efficiency Design Index (EEDI) guides the future development of the shipbuilding industry toward green ships and accelerates the pace of energy conservation and emission reduction. EEDI is closely related to hull form; therefore, the design optimization of ship hull focus on reducing EEDI becomes the central issue of the current research (Hou et al. 2018).
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Waskito, Kurniawan Teguh, and Yanuar. "On the High-Performance Hydrodynamics Design of a Trimaran Fishing Vessel." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 83, no. 1 (June 3, 2021): 17–33. http://dx.doi.org/10.37934/arfmts.83.1.1733.
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Trimaran hull form as multihull ship becomes more attractive these days in various ship types. It offers more advantages in terms of seakeeping performances, particularly on the application of a fishing vessel. However, thus far, the conventional design of fishing vessels is not favorable to ensure the safety of a vessel sailing in a rough sea. In conjunction with such issues, we discuss a trimaran fishing vessel design based on the seakeeping criterion to evaluate the dynamic stability, ship motion RAOs, and ship resistances at the initial design stages using linear strip theory. The intact stabilities are calculated to complement the seakeeping results. The analytical method based on the slender body method is used to evaluate the steady wave resistances. The results of heave, pitch, roll motions, and the ship resistances are discussed. At the zero speed and forward speed, the trimaran shows a favorable motion amplitude, although in forward speeds at the case of head seas there is no significant difference. The trimaran presents a favorable steady-resistance up to the ship speed of Fn=0.27, and it becomes deteriorating than the monohull at higher ship speeds. However, the added wave resistances of the wavelength range 1.0 – 3.0 shows significant added resistances at Fn=0.25 and Fn=0.35, respectively. The results of this study present promising seakeeping and resistance characteristics of the trimaran hull form. The trimaran hull form ensures the safety, reliability, and operation efficiency of ships sailing in broader ranges of violent-sea environment.
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Suastika, Ketut, and Fajar Nugraha. "Effects of Parallel-Middle-Body Relative Length and Stern Form on the Wake Fraction and Ship Resistance." Applied Mechanics and Materials 862 (January 2017): 278–83. http://dx.doi.org/10.4028/www.scientific.net/amm.862.278.
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Effects of parallel-middle-body relative length and stern form of a 10450-DWT tanker on the wake fraction and ship resistance are studied by using computational fluid dynamics (CFD). Calculations were done with varying ratios of parallel-middle-body length to ship length (Lmb/L) and with varying stern forms. The same ship displacement is maintained in all the calculations. It is found that a larger value of Lmb/L for ships with the same stern form results in a larger ship resistance but does not affect the wake fraction significantly. A more abrupt stern form results in a larger wake fraction and in a much larger ship resistance. In the former case, the increase of ship resistance is ascribed to the increase of the wetted surface area (WSA) of the ship and in the latter case particularly to the much larger wake fraction.
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Guo, Chunyu, Xianghai Zhong, and Dagang Zhao. "Research on Scale Effect of Resistance Components for Full-Formed Ship Based on Large-Scale Model Towing Test." Journal of Marine Science and Engineering 11, no. 7 (June 26, 2023): 1300. http://dx.doi.org/10.3390/jmse11071300.
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In recent years, the International Maritime Organization (IMO) has gradually introduced more stringent new Ship Energy Efficiency Design Index (EEDI) bills, and transport ships are more inclined to reduce the speed and increase the length and square coefficient to meet the design requirements. However, the size of the ship model that can be accommodated in the towing tank is seriously limited. Under the action of the scale effect, the accuracy of the prediction results of the resistance performance of large ships is particularly prominent. To break through the limitations of the test site, a large-scale ship model resistance towing test system and data analysis method in the port were established. By comparing with the results of small-scale model tests in the towing tank, the applicability of the 1957 ITTC friction line and Grigson friction line in the resistance prediction of the full-formed ship was analyzed, and the scale effects of resistance components were also examined. The results show that the scale effect of the form factor of full-formed ships is weak. The three-dimension method based on the empirical formula of mixed-form friction resistance of ITTC-Grigson is more suitable for predicting the resistance performance of full-formed ships.
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Martić, Ivana, Nastia Degiuli, Dubravko Majetić, and Andrea Farkas. "Artificial Neural Network Model for the Evaluation of Added Resistance of Container Ships in Head Waves." Journal of Marine Science and Engineering 9, no. 8 (July 30, 2021): 826. http://dx.doi.org/10.3390/jmse9080826.
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The decrease in ship added resistance in waves fits into both the technical and operational measures proposed by the IMO to reduce the emissions of harmful gases from ships. Namely, the added resistance in waves causes an increase in fuel consumption and the emission of harmful gases in order for the ship to maintain the design speed, especially in more severe sea states. For this reason, it is very important to estimate the added resistance in waves with sufficient accuracy in the preliminary design phase. In this paper, the possibility of applying an ANN to evaluate added resistance in waves at the different sea states that the ship will encounter during navigation is investigated. A numerical model, based on the results of hydrodynamic calculations in head waves, and ANN is developed. The model can estimate the added resistance of container ships with sufficient accuracy, based on the ship characteristics, sailing speed, and the sea state using two wave energy spectra.
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Martić, Ivana, Nastia Degiuli, and Carlo Giorgio Grlj. "Prediction of Added Resistance of Container Ships in Regular Head Waves Using an Artificial Neural Network." Journal of Marine Science and Engineering 11, no. 7 (June 25, 2023): 1293. http://dx.doi.org/10.3390/jmse11071293.
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In this paper, an artificial neural network was used to predict the added resistance coefficient for container ships in regular head waves for various speeds. The data used for training the neural network were gathered based on performed numerical calculations using the Boundary Integral Element Method for various hull forms of container ships. The numerically obtained results were validated against the available experimental data for three benchmark container ships. The data were divided into three classes based on the ship length, and the expressions for the prediction of the added resistance coefficient for each container ship class were provided. The performance and generalization properties of the neural network were evaluated based on the normalized value of the root mean square error. The model enables reliable prediction of the added resistance coefficient within the preliminary design stage of a ship based on the ship characteristics and speed.
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Sun, Jianqiao, and Yan Huang. "Experimental Study on the Ice Resistance of a Naval Surface Ship with a Non-Icebreaking Bow." Journal of Marine Science and Engineering 11, no. 8 (July 30, 2023): 1518. http://dx.doi.org/10.3390/jmse11081518.
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With the shrinking of Arctic sea ice due to global climate change, potential access to Arctic waters has increased for non-typical icebreaking or strengthened ships. Numerous studies have been conducted on hull form designs and ice resistance predictions for ships with typical icebreaking bows, but published research for ships with non-icebreaking bows in ice is still rare. The objective of this study was to investigate the ice resistance of a naval surface ship with a non-icebreaking bow through model tests in an ice tank. The naval surface combatant concept DTMB 5415 was used as the ship model. The tests were conducted under different levels of ice thicknesses and speeds. During the tests, the total resistance of the model ship was measured, accompanied by monitoring of the ice load at the stem area with a flexible tactile sensor sheet. Compared with the test results of icebreaker models in former studies, the total ice resistance, as well as the stem ice load, of the present ship was significantly higher. The ice crushing resistance component in the stem area accounted for more than 60% of the total resistance in the ice. Discussions on the applicability of a semi-empirical formula for predicting the ice resistance of the present ship are also presented. Keinonen’s formula was found to be relatively more consistent with the predictions produced by model tests, and a preliminary modification was proposed to obtain more accurate predictions.
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Qi, Luyao. "The application of bionics in optimizing ship resistance reduction." Applied and Computational Engineering 7, no. 1 (July 21, 2023): 793–800. http://dx.doi.org/10.54254/2755-2721/7/20230507.
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Since humans and nature have a shared destiny, harmony is the way for the two to get along. Learning from nature can lead to long-term and steady development for humans. Bionics is an emerging discipline that learns from nature modestly. The structure and products of the best organisms in species evolution work as a beacon for scientific and technological progress. In the field of ship fluid mechanics, the combination of bionics and ship and ocean engineering provides many simple and effective design schemes for the fluid performance optimization of ship materials and structures. This paper mainly summarizes and discusses the research and application status of bionics in the field of ship fluid drag reduction from four aspects, namely the imitation of biological shape, biological epidermal texture, biological function, and biological structure. Conclusions can be drawn that bionics can used to improve a ships shape, structure, surface materials, and marine coatings to optimize ship fluid performance and effectively reduce ship drag.
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Michalski, Jan. "A parametric method for evaluation of resistance of swath ships." Polish Maritime Research 15, no. 1 (January 1, 2008): 3–10. http://dx.doi.org/10.2478/v10012-007-0045-6.
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A parametric method for evaluation of resistance of swath ships This paper contains formulation of a parametric method for evaluation of SWATH ship's hull resistance. The method was elaborated on the basis of numerical calculation results obtained by using structural methods based on ship hydrodynamic theory and performed for sufficiently large series of body forms with systematically changing ship form parameters. Also, results of verifying investigations dealing with features of the method in question are presented by comparing the obtained resistance characteristics with those achieved by other authors as well as with ship model experimental test results. The obtained results of the verification indicate that the elaborated method can be useful in preliminary designing the SWATH ships.
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Wei-Hann, Khor, Siow Chee Loon, Adi Maimun Abdul Malik, Arifah Ali, Mohammad Nabil Jainal, and Jonathan Yong Chung Ee. "Investigate the Drag Resistance of Antifouling Self-Adhesive Film." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 77, no. 2 (November 14, 2020): 13–22. http://dx.doi.org/10.37934/arfmts.77.2.1322.
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Fouling has always been a common issue for ships as fouling drastically increases the surface roughness and ship resistance. The microfiber self-adhesive antifouling film is claimed to be effective up to 5 years and is environmentally friendly. However, there is lack of information about the drag characteristics of the antifouling material. Thus, this project is conducted based on an experimental study to determine the drag characteristics of the surface installed with microfiber self-adhesive antifouling film. The rotor apparatus is used to study the coefficient of friction of the microfiber surface. From the experimental results, a flat plate simulation using ANSYS-Fluent is conducted to further estimate the coefficient of friction up to Reynolds number of 109 and to evaluate the total ship resistance for the Semi-SWATH (fast vessel) and KVLCC (slow trading ships). The results show that the percentage increase in total ship resistance for the KVLCC is about 80%, which is more than the Semi-SWATH of 30%, as frictional resistance has high significance for slow trading ships. The speed drop experienced by the ship model installed with the microfiber antifouling is 2 knots for the KVLCC and 1 knot for the Semi-SWATH if the power remained the same for both models.
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Cahyadi Sugeng, JM, Semin, and Erwandi. "The study of the Modification of the Ro-Ro Ferry’s Angle of the Entrance Using Statistical Methods and Ship Model Resistance Tests." IOP Conference Series: Earth and Environmental Science 1081, no. 1 (September 1, 2022): 012018. http://dx.doi.org/10.1088/1755-1315/1081/1/012018.
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Abstract Aspects of speed and its correlation to ship resistance greatly affect the performance of ferry ro-ro ships. The fixing of the ship’s resistance is very significant when related to the ship’s economic costs. BTH-BRIN has carried out resistance tests and calculations using the Holtrop statistical method where the resistance result is considered too large. To reduce the resistance, modifications are made, one of which is by changing the angle of the entrance of the ship bow. Again, the Holtrop statistical calculations are then employed to determine the effective angle of the entrance after the ship is modified. Reducing the angle of the entrance of water at the ship’s bow is expected to reduce the resistance in terms of the bow wave. It also needs paying attention to the amount of ship payload that has been planned. This paper describes the process of resistance reduction due to the change of the angle of the entrance of the ferry ro-ro ship. Firstly the resistance of the original ship is predicted using the statistical method and a scaled ship model is made and tested in BTH towing tank. Second, the angle of the entrance of the ferry ro-ro ship is modified. Finally, the modified one is predicted statistically based on the Holtrop method. The results of the statistical analysis of the modified angle of entrance showed that the resistance is smaller than the original one.
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Le, Quang, Huong Thi Thanh Pham, and He Van Ngo. "Experimental Study and Application of CFD During the Exploitation Process of Ship in Order to Minimizing the Fuel Consumption." Science and Technology Development Journal 18, no. 4 (December 30, 2015): 136–44. http://dx.doi.org/10.32508/stdj.v18i4.999.
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The acticle presents a method for minimizing energy exploitation of the ship through reducing ship resistances. Ship resistances include water resistances caused by frictions of water and waves acting on hull part in the water and air resistance acting on the hull part above water surface. To reduce the resistance caused by water friction, the authors proposed a method which intervene directly on the boundary layer of ship hull by the creating a gas injection foaming layer. To reduce air resistance, the authors used CFD method to optimaze arrangement of container on deck for a container ship. Obtained results showed that the proposed method help to save 5-8% of the consuming energy.
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Utomo, Budi, and Sulaiman Sulaiman. "ANALISIS NILAI HAMBATAN TOTAL DENGAN PERUBAHAN SARAT KAPAL KM. KENDHAGA NUSANTARA 6." Gema Teknologi 21, no. 1 (October 30, 2020): 21–25. http://dx.doi.org/10.14710/gt.v21i1.32875.
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The calculation of total resistance value is important of ship because affects the speed of fluid flow that occurs, as well as the speed of the ship.So that in the designing new ships, sea trials are needed to find out whatever the preparedness of the ship is planned. The purpose is to obtain the value of the total resistance and the coefficient of ship resistance KM. Kendhaga Nusantara 6 uses the calculation method for each ship draught/loading condition. The Method used is experimental method with numerical value approach, Denny Mumford theory and Froude's number. The results show that the largest Total Resistance (Rt) is 5646,02 kN, it was found when speed of ship was 12 knots and draught ship 3,5 meters, with a coefficient value (Ct) of 7,757 x 10-3. The difference in value (Ct) is 0,032x10-3 or 0.41%, and it is still in the criteria because it is below 5%.
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Sun, Haisu, Xuan Ni, Yuxin Zhang, Kang Chen, and Baoyu Ni. "A Numerical Prediction of the Resistance of Bulk Carriers in Brash Ice Channels." Journal of Marine Science and Engineering 11, no. 7 (July 16, 2023): 1425. http://dx.doi.org/10.3390/jmse11071425.
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Ship resistance increases significantly when navigating a brash ice channel. In this study, the numerical method is applied to predict the full-scale ship resistance of bulk carriers in brash ice channels. The viscous flow computational fluid dynamics (CFD) solver was coupled with the discrete element method (DEM) to establish the brash ice model. The Euler multiphase flow’s volume of fluid (VOF) model was applied to simulate the interaction between the ship and water. The ship–brash ice interaction was simulated. Predictions of ships’ total resistance based on the numerical method and the Finnish Swedish ice class rules (FSICR) method were compared with the experimental results carried out in Hamburg Ship Model Basin (HSVA) ice tank. The numerical resistance shows a good agreement with the HSVA experiment reports and a better performance than the FSICR method. The present study shows that the numerical method could provide reasonable and practical ice resistance predictions for engineering applications.
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Kautsar, Nafiri Muhammad, and I Ketut Suastika. "Analysis of The Effect of Hull Vane Lifting Force on Fast Vessel Resistance: Straight Hull Vane." WAVE: Jurnal Ilmiah Teknologi Maritim 17, no. 1 (August 13, 2023): 22–33. http://dx.doi.org/10.55981/wave.2023.926.
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In previous studies by Saputra, the use of straight Hull Vane® increased ship's resistance. Based on hypothesis, this was caused by lifting force from Hull Vane® being too large, so that ship experienced bow trim. To reduce bow trim, smaller Hull Vane® was made including Hull Vane® with AR = 8.5, AR = 22.9 and AR = 28.94 with speeds which were 11 knots (Fn = 0.34), 17 knots (Fn = 0.53), 20 knots (Fn = 0.62) and 26 knots (Fn = 0.8). From simulation results, it was found that use of a straight Hull Vane® in every aspect ratio variation on vessel was only effective at 11 knots speed which could reduce ship's resistance up to 17%. For speeds above 11 knots, increased in aspect ratio can reduce resistance but resistance on ships with straight Hull Vane® was still greater than on ships without Hull Vane® because lift force by Hull Vane® at ship stern was still too large, so the bow of ship was more submerged than ship without Hull Vane®. This caused value of the wetted surface area (WSA) and value of hydrodynamic pressure more increased than ships without Hull Vane®, so value of ship's resistance also increased.
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Rahmat Azis Nabawi, Syahril, and Primawati. "Study Reduction of Resistance on The Flat Hull Ship of The Semi-Trimaran Model: Hull Vane Vs Stern Foil." CFD Letters 13, no. 12 (December 17, 2021): 32–44. http://dx.doi.org/10.37934/cfdl.13.12.3244.
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Flat hull ships is appraised for its superiority due to the manufacturing simplicity and lower investment costs, yet the ship has its own weakness for it requires a greater resistance. As a matter of fact, a significant reduction on the resistance can be done with foil installation but it is necessary to study the optimal position of the foil installation. This study is aimed at revealing the effectiveness of the Hull Vane and Stern Foil installation in reducing the resistance experienced by the flat hull ship of the semi-trimaran model. The research was conducted by comparing the resistance experienced by the flat hull ship of the semi-trimaran model without foil, Hull vane and Stern foil installations. In addition, the disclosure of resistance experienced by each ship model was carried out by using CFD simulation. The simulation results revealed that the installation of the Hull vane and Stern foil was able to reduce the resistance experienced by the flat hull ship of the semi-trimaran model. The largest reduction occurred in Froude number 1.1, where the Hull vane installation was able to reduce resistance by 12.44% and on the ship model with Stern foil installation the resistance reduction was 5.25%. Based on the results of this CFD simulation, it can be concluded that the Hull Vane installation is more optimal in reducing resistance on the flat hull ship of the semi-trimaran model.
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Rahaman, Md Mashiur, H. Islam, H. Akimoto, and M. R. Islam. "Motion predictions of ships in actual operating conditions using potential flow based solver." Journal of Naval Architecture and Marine Engineering 14, no. 1 (June 28, 2017): 65–76. http://dx.doi.org/10.3329/jname.v14i1.28674.
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Prediction of ship's response in real voyage condition is essential for efficient ship design. At sea, ships rarely voyage in head wave conditions, and mostly prefer oblique waves for lower resistance and better propulsion. This paper provides oblique wave simulation results for a container, tanker and bulk carrier using a commercial potential flow (PF) based solver, HydroSTAR. Although, PF codes have limitation regarding resistance prediction, they are well reliable in predicting ship motion in waves. The paper aims at providing a relative comparison of ship resistance and motion in different heading angles for three major ship models namely KCS, KVLCC2 and JBC. The paper should prove useful to shippers in case of weather routing or route selection for voyage.
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Charchalis, Adam. "Estimation of the Vessel's Sailing Resistance in the Preliminary Analyses." Journal of KONES 26, no. 1 (March 1, 2019): 17–22. http://dx.doi.org/10.2478/kones-2019-0002.
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Abstract In this article is presented the methodology of calculation of principal parameters of hull a vessel and resistance components. The approximate method is based on the analysis of the results of model tests and surrender tests presented in the literature. Ship owners' preliminary assumptions for new ship consist of deadweight, speed-shipping line and others. This goal needs definition of principal dimensions of a vessel, which are the basis for further calculations of hull’s resistance and evaluation of necessary power of main engine to fulfil shipping requirements. The route and its environment, type of cargo, quantity to be moved, and value of the cargo and port facilities are typical features, which will be considered when evolving the size, speed, and specification of a suitable ship. Specific service requirements will be similarly considered when evolving vessels such as warships, passenger ships or fishing vessels. Selection of main dimensions of vessel is limited by related to seaways or harbours characteristic and limitations rules regarding buoyancy, stability, hull strength, manoeuvring capability, etc. The influence of the main dimensions of the ship and their coefficients of maritime and strength properties of the ship were presented. Moreover, formulas for calculation of the ship's resistance components, such as friction resistance, and wave shape, as well as the results of calculations for different types of ships, for the assumed deadweight and speed of sailing, are presented.
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Feng, Dakui, Bin Ye, Zhiguo Zhang, and Xianzhou Wang. "Numerical Simulation of the Ship Resistance of KCS in Different Water Depths for Model-Scale and Full-Scale." Journal of Marine Science and Engineering 8, no. 10 (September 26, 2020): 745. http://dx.doi.org/10.3390/jmse8100745.
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Estimating ship resistance accurately in different water depths is crucial to design a resistance-optimized hull form and to estimate the minimum required power. This paper presents a validation of a new procedure used for resistance correction of different water depths proposed by Raven, and it presents the numerical simulations of a Kriso container ship (KCS) for different water depth/draught ratios. Model-scale and full-scale ship resistances were predicted using in-house computational fluid dynamics (CFD) code: HUST-Ship. Firstly, the mathematical model is established and the numerical uncertainties are analyzed to ensure the reliability of the subsequent calculations. Secondly, resistances of different water depth/draught ratios are calculated for a KCS scaled model and a full-scale KCS. The simulation results show a similar trend for the change of model-scale and full-scale resistance in different water depths. Finally, the correction procedure proposed by Raven is briefly introduced, and the CFD resistance simulation results of different water depth/draught ratios are compared with the results estimated using the Raven method. Generally, the reliability of the HUST-Ship solver used for predicting ship resistance is proved, and the practicability of the Raven method is discussed.
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Sun, Jianglong, Xujian Lv, Weibin Liu, Hanwen Ning, and Xianwen Chen. "Research on a method of hull form design based on wave-making resistance optimization." Polish Maritime Research 19, no. 3 (October 1, 2012): 16–25. http://dx.doi.org/10.2478/v10012-012-0027-1.
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ABSTRACT In this paper, we consider an optimization of the hull shape in order to minimize the total resistance of a ship. The total resistance is assumed to be the sum of the wave resistance computed on the basis of the thin-ship theory and the frictional resistance. Smoothness of hull lines is proved with mathematical procedure, in which differentials of the hull lines functions are analyzed. The wave-making resistance optimization, involving a genetic algorithm, uses Michell integral to calculate wave resistance. A certain hull form is generated by the method using cross section information of a modified DTMB model ship 5415 and a comparative experiment is carried out. Experimental and calculation result show that the method is of good adaptability for designing certain types of ships with excellent resistance performance.
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Nguyen, Van Trieu, Minh Duc Le, Van Minh Nguyen, Toru Katayama, and Yoshiho Ikeda. "Influences of Gap Flow on Air Resistance Acting on a Large Container Ship." Journal of Marine Science and Engineering 11, no. 1 (January 9, 2023): 160. http://dx.doi.org/10.3390/jmse11010160.
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In terms of speed lost and fuel consumed, wind loads are considered one of the main factors for large ship design, especially for container ships. Alongside water resistance, air resistance in strong wind conditions has a significant impact on the fuel efficiency and performance of container ships with large box-type bodies. This paper reports the effects of wind loads acting on a 20,000 TEU container ship carrying large numbers of deck containers using a commercial CFD software program (ANSYS Fluent V14.5 with RANS equation). A 1/255.3 scale model was used in this study to reveal the air resistance on the container ship configuration. The aerodynamic formations of the complex vortices, pressure, velocity contours, and streamlines, as well as the air forces acting on the container ship, are presented and discussed. The pressure distributions show that the gap air flows increase the stagnation pressure at the face side and decrease the pressure on the backside of each container gap through separate eddies. The difference in pressures created in the gaps contribute to the air resistance acting on the ship. It is confirmed that the use of side covers of deck containers to close the gap flows between container blocks can significantly reduce the air resistance for wind directions in the range of 30 to 60 degrees.
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Luk, C. H. "A Three-Dimensional Plasticity and Momentum Model for Ship Resistance in Level Ice." Journal of Offshore Mechanics and Arctic Engineering 113, no. 1 (February 1, 1991): 53–60. http://dx.doi.org/10.1115/1.2919896.
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In this paper, a three-dimensional analysis is presented for calculating the level ice resistance for ships that have conventional hull forms. Comparisons with published ship resistance data and other analytical predictions are also provided. The present approach combines two analytical techniques: 1) plastic limit analysis is used to describe the ice failure mechanism and the associated ice velocity field; and 2) linear and angular momentum balances determine the average ice resistance for a ship. In the momentum balance, potential flow theory is used to describe the water motion induced by the icebreaking process. Existing methods for determining ship resistance in ice include numerical methods which depend on solutions of equations of motion that describe the dynamic interaction between the ice and the ship, and empirical methods which depend on model and full-scale icebreaker data to generate empirical correlations for ship resistance. The present results compare reasonably well with published model-scale and full-scale icebreaker data. Comparisons with predictions based on other numerical methods are also discussed.
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Tian, Xiaoqing, Tianwei Xie, Zhangming Liu, Xianghua Lai, Huachen Pan, Chizhong Wang, Jianxing Leng, and M. M. Rahman. "Study on the Resistance of a Large Pure Car Truck Carrier with Bulbous Bow and Transom Stern." Journal of Marine Science and Engineering 11, no. 10 (October 7, 2023): 1932. http://dx.doi.org/10.3390/jmse11101932.
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The resistance of a large Pure Car Truck Carrier (PCTC) with a bulbous bow and a transom stern is evaluated in the present paper. Several cases at nine different ship speeds in calm water are simulated and results are compared with the experimental measurements. The maximum relative error is 0.93% at a Froude number (Fr) of 0.209. The total resistance coefficient of the ship in calm water shows a parabolic trend with increasing Fr, and it reaches a minimum value at Fr = 0.1794. Furthermore, the cases of the ship in regular waves with six different wavelengths and three wave heights are simulated. It is observed that the total resistance exhibits a quadratic relationship with the wavelength when the wave height is fixed. The wave-making resistance increases with the increase in wave height at any fixed wavelength, and it reaches a maximum value when the wave-length is 1.2 times the ship length (Lpp). Additionally, we also investigated the resistance in three different sea states at four different speeds. When the significant wave height of irregular waves is the same as regular waves, the wave-making resistance under irregular waves is much smaller than that of the regular waves. All of these results indicate that the bulbous bow and transom stern can reduce the wave-making and residuary resistances, which can provide a useful reference for the subsequent design and manufacturing of related ships.
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Iqbal, Muhammad, Parlindungan Manik, Eko Sasmito Hadi, and Achmad Kurniawan. "PENGARUH POSISI CENTERBULB BERBENTUK FOIL TERHADAP KOMPONEN HAMBATAN KAPAL IKAN KATAMARAN MV. LAGANBAR." JURNAL INTEGRASI 12, no. 1 (April 22, 2020): 64–71. http://dx.doi.org/10.30871/ji.v12i1.1885.
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Catamarans are double hull ships which have many advantages over single hull ships with the same displacement. To increase catches, fishermen in Cilacap converted ships from the original single hull with outrigger to double hull (catamaran). Displacement of ships has doubled. But the ship's resistance increased to almost 4 times. To reduce the resistance of catamarans, some researchers use the concept of center bulb. In this study, the center bulb form used foil. The purpose of this study was to determine the effect of center bulb position on ship resistance components by comparing 9 center bulb positions. The results stated that of the nine center bulb position configurations, Model 6 is the best model because at Fr 0.35 it can reduce ship resistance by up to 33%. For the viscous resistance component it is not significantly affected by the use of the center bulb. But on the wave resistance component, the use of this center bulb can reduce wave resistance by 47% at Fr 0.35.
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Yang, Bo, Sami Kaidi, and Emmanuel Lefrançois. "CFD Method to Study Hydrodynamics Forces Acting on Ship Navigating in Confined Curved Channels with Current." Journal of Marine Science and Engineering 10, no. 9 (September 7, 2022): 1263. http://dx.doi.org/10.3390/jmse10091263.
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The bending section of the restricted channel is one of the most accident-prone areas for inland ships, but few clear investigations on the curvature effect have been conducted till now. Therefore, this paper presents numerical research of the curvature effect in confined bending channels on ship hydrodynamics. The unsteady Navier–Stokes equations closed by the realizable K-Epsilon turbulence model are utilized to simulate the flow around a three-dimensional inland ship. A mesh verification analysis is performed to select the most suitable grid size, and the CFD model is validated in a regular confined channel by comparing the numerical resistance forces with those from experiments. The impacts of the channel slope angle, channel radius, ship type (ship length), and current velocity in curved channels on ship hydrodynamics are studied with their influence patterns and mechanisms being analyzed in detail. Results show that channel radius only affects the yaw moment much, whereas ship hydrodynamics are greatly sensitive to the slope angle only when the angle is below a certain threshold value. Compared with short ships, much stronger spiral currents can be noticed passing through long ships in the same channel configuration. Current velocity affects both resistance and yaw moment a lot, with a critical current velocity for sway force.
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Cole, S. L. "Low-Aspect-Ratio Flat Ship Theory for Moderate Froude Numbers." Journal of Ship Research 35, no. 04 (December 1, 1991): 325–30. http://dx.doi.org/10.5957/jsr.1991.35.4.325.
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Low-aspect-ratio flat ship theory models ships whose dimensions satisfy draft << beam <<length. This paper systematically derives the inner and outer linearized problems for moderate Froude number potential flow past such a ship and their solutions. These solutions are matched through an intermediate region. It is found that the leading-order term for the wave resistance for moderate speed low-aspectratio flat ship theory is the same as found in slender ship theory for ships with equivalent cross-sectional areas. Flat ship theory, however, predicts singularities in the flow along the outside of the ship's leading edge which are not present in slender ship theory. A simple example demonstrating these spurious singularities is worked out.
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Liu, Kaihua, Yu Wang, Zhifei Wu, Juntao Pi, Wie Min Gho, and Bo Zhou. "Numerical Simulation on Dynamic Characteristics of Longitudinal Launching of Large Container Ships." Journal of Marine Science and Engineering 10, no. 11 (October 26, 2022): 1583. http://dx.doi.org/10.3390/jmse10111583.
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The upsizing and rapid development of container ships has resulted in many large ships launching in small slipways due to the lagging of advanced equipment. In particular, the dynamic characteristics of these large ships in the longitudinal launching operation under restricted water are yet to be studied in detail. In this study, a ship model to simulate the longitudinal launching process of an 8500 TEU container ship was created based on the URANS method. The ship resistance in calm water was determined and validated against the experimental data. The influence of the stern appendage on the ship’s resistance and the flow field around the hull, with and without the aft poppet, under various water-depth-to-draught ratios was analyzed. A comparison of the ship’s resistance between the numerical and the experimental data shows that the difference is minimal, within 1.5%. The numerical results revealed that the aft poppets change the flow pattern and effectively reduce the pressure drag in the drifting stage. The shallow water causes a restraining effect on the ship. The proposed analytical approach in the numerical analysis, considering the aft poppet and the water depth, could provide a better simulation for a large ship’s longitudinal launching operation.
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Watanabe, Seiya, Changhong Hu, and Takayuki Aoki. "Coupled Lattice Boltzmann and Discrete Element Simulations of Ship-Ice Interactions." IOP Conference Series: Materials Science and Engineering 1288, no. 1 (August 1, 2023): 012015. http://dx.doi.org/10.1088/1757-899x/1288/1/012015.
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Abstract Evaluating ice loads acting on ships is essential for the safety of ships navigating in ice-covered seas. In this study, we develop a CFD method to handle ship, ice, and fluid interaction. The lattice Boltzmann method, capable of large-scale calculations, is applied to the simulation of free-surface fluids. The ice motion is computed by solving the equations of motion of a rigid body, and the discrete element method models the ice-ice and ice-ship contact interactions. A momentum exchange scheme couples the lattice Boltzmann method and particle-based rigid body simulation. We introduce tree-based adaptive mesh refinement and multiple GPU computing to improve grid resolution and computational time. The proposed method is applied to model scale simulations of ship navigation in a brash ice channel. Simulations were performed for various conditions with different ice concentrations and ship velocities, and we observed that ice resistance increased with the ice concentration and the ship velocity increased. The ice motions and resistances obtained from our simulations are reasonable compared to model equations of Finnish-Swedish ice class rules (FSICR) and numerical analyses of a previous study.
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Lü, Yan Song, and Zhi Yuan Mei. "Study on Collision Damage Behavior of Ship." Advanced Materials Research 594-597 (November 2012): 2689–92. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.2689.
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Ship collision is a kind of dangerous accident which may result in serious damage of struck hull structure during shipping process. The damage of ship depends on the relative rigidity of striking ship and the capabilities of crash resistance of ship structures. The rigidity of bow is always considered as higher than that of side, so the structure of bow is regarded as rigid body. But this method is so conservative that the result of numerical simulation may be wrong when the rigidity of side of one ship is higher than that of bow of another ship. The process of collision of two ships is simulated, in which the structures of two ships are all defined as elastic body. The behavior of side is studied and some useful results are found.
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Xie, Yao Guo. "Shock-Resistance Research of Ship Structural Subjected to Underwater Explosion." Advanced Materials Research 945-949 (June 2014): 1180–84. http://dx.doi.org/10.4028/www.scientific.net/amr.945-949.1180.
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A finite element model ships, for example design test condition of the underwater explosion, selection of explosive package quantity is 1000KG TNT, the explosive location along the direction of the ship with the bow, midship and stern, the angle of attack in three exploded cross section have 90 degrees, 60 degrees, 45 degrees, 30 degrees and 0 degrees. According to the current standard to calculate the ship damage radius, critical radius and safety radius of specific values under the effect of underwater explosion, interpolation calculation and draw the envelope. Analysis shows that the vitality of ships and shock-resistance is not only related to the explosive distance, also related to the attack position.
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Xue, Wen, Zhiliang Gao, and Sangming Xu. "Numerical Study on Attitude and Resistance of a Side-Damaged Ship during Steady Flooding." Journal of Marine Science and Engineering 10, no. 10 (October 6, 2022): 1440. http://dx.doi.org/10.3390/jmse10101440.
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The computational fluid dynamics method is used to analyze the attitude and resistance of a side-damaged frigate DTMB-5415 during steady flooding phase. The volume of fluid method is used to capture the interface between water and air. The shear stress transport k-ω model is employed to include the turbulence effect. The dynamic overlapping grid method is utilized to deal with the mesh update due to the ship motion in the simulation. First, the resistance, floating position and wave profile of an intact ship for different forward speeds are calculated. By comparing the results with experimental data, the calculation method is verified. Then, the resistances, attitudes and flow fields for the ship in intact, side-damaged (symmetrical and asymmetric flooding) and damage-repaired conditions are calculated and compared. For the side-damaged condition, the main change of the ship’s attitude is that the ship’s sinkage increases as the forward speed increases. Compared with symmetrical flooding, the ship’s heel increases during asymmetric flooding, while the sinkage decreases. For symmetrical flooding, the resistance of the ship increases significantly compared to the intact ship case. The increased resistance is mainly caused by the increase of ship sinkage. The existence of opening that affects the flow field causes additional increase of ship resistance. The pressure resistance is the main component of increased resistance, which is similar to the asymmetric flooding case.
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Yao, Rulin, Long Yu, Qidong Fan, and Xuefeng Wang. "Experimental and Numerical Resistance Analysis for a Cruise Ship W/O Fin Stabilizers." Journal of Marine Science and Engineering 10, no. 8 (July 31, 2022): 1054. http://dx.doi.org/10.3390/jmse10081054.
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Applying fin stabilizers is an effective solution for ship rolls on waves in a seaway. They generally consist of one or two pairs of retractable fins that are symmetrically mounted to both sides of the ship, effectively reducing the roll motion at low or moderate speeds. Fin stabilizers are commonly used by cruise ships for the comfort and safety of passengers. However, there is still little experimental and numerical analysis of the fins’ effect on hydrodynamic performance. In this study, the resistance performance of a cruise ship was investigated with/without fin stabilizers at different fin angles and ship velocities by model tests and numerical analysis. The CFD analysis provides a flow-detailed interpretation of the physical phenomenon, especially at an asymmetric maximum fin angle. The significant fin-induced resistance is newly discovered and averages up to 19% in calm water conditions, while the added resistance in waves is evaluated with a smaller increment up to 1.31%. By comparing the numerical and experimental results, this study provides insight into the resistance induced by overhanging fins, which provides an accurate prediction reference for cruise ship performance and benefits the fin stabilizers’ design and selection.
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Huang, Ya Nan, Da Lu Liu, Feng Sheng Sun, Da Yong Zhang, and Dong Lu. "Research on Optimum Design of Molded Lines of the Bulbous Bow of a Container Vessel." Advanced Materials Research 510 (April 2012): 417–23. http://dx.doi.org/10.4028/www.scientific.net/amr.510.417.
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In this paper, taking a 7000 TEU container ship as an example, research on optimization design of mold lines of bulbous bow for container ships is carried out. Firstly, geometric parameters of bulbous bow are selected to be as variables to construct 7 computing molds, then CFD methods are employed to calculate ship resistance and parameters of wave field generated by ship moving, as well as Michell integration is used to determine the coefficient of wave-making resistance. Minimization of resistance is taken as the aim function to obtain the optimum geometric parameters of mold lines at bow. The results of mold testing express that the mold lines of bulbous bow for container vessel optimized by above methods are credible and valuable for engineering practice.
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Han, Shuai, Lin Yang, and Qidan Zhu. "Numerical Simulation of Ship-added Resistance Based on a Numerical Wave Tank." Journal of Physics: Conference Series 2747, no. 1 (May 1, 2024): 012039. http://dx.doi.org/10.1088/1742-6596/2747/1/012039.
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Abstract The wave resistance increase of a ship during its actual voyage can affect its speed and safety. To design ships with excellent sailing performance, it is necessary to accurately predict the wave resistance increase of a ship in waves, as well as the motion response and wave resistance prediction of ships in waves, which involves complex hydrodynamic problems. This paper first establishes a physical model of the KCS vessel, then utilizes the numerical wave tank platform independently developed by our university. Based on viscous flow theory, it calculates the resistance of the KCS under calm water conditions. Using three-dimensional potential flow methods and spectral analysis, it computes the wave-induced resistance values for the KCS under six-degree sea states, analyzes the wave-induced resistance performance of the KCS, and ultimately, based on the calculation results of calm water resistance and wave-induced resistance combined with propeller efficiency parameters, calculates the effective power of the engine.
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Domnișoru, Leonard. "Preliminary hydrodynamic analyses for a river research ship. comparative study of mono-hull and catamaran ship type." Analele Universităţii "Dunărea de Jos" din Galaţi Fascicula XI Construcţii navale/ Annals of "Dunărea de Jos" of Galati Fascicle XI Shipbuilding 46 (December 4, 2023): 39–46. http://dx.doi.org/10.35219/annugalshipbuilding/2023.46.05.
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The design in early stages of the ships involves several preliminary hydrodynamic analyses, also for the ship operating on river waterways, IN(1.2) navigation class. This technical paper includes two main parts as preliminary assessment for the design constructive versions of a river research ship. The first part is focused in the comparative study of the mono-hull and the catamaran ship design by seakeeping and global strength criteria. The second part is focused on the ship resistance for two mono-hull versions of the river research ship. The study hydrodynamic preliminary results are the initial bases for proper design in next steps of the river research ship.
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Supryatno, Adi, and Sischa Andriani Alimin. "Gambaran Infestasi Vektor pada Kapal Penumpang dan Kapal Barang yang Sandar di Pelabuhan Baubau." JOURNAL OF BAJA HEALTH SCIENCE 2, no. 01 (February 24, 2022): 78–84. http://dx.doi.org/10.47080/joubahs.v2i01.1901.
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ABSTRACT
High transportation needs can cause health problems, such as vector infestation. Vector infestation is most likely caused by the behavior of the crew, the age of the ship, the number of passengers, the cleanliness of the ship, and resistance to continuous use of pesticides. The purpose of this study was to describe the location of vector infestations on passenger ships and cargo ships that dock at Baubau port. This type of research is a quantitative descriptive using a cross sectional study design. The object of this research is the ships that docked at the Bau-bau port in December 2017 as many as 12 passenger ships and 12 cargo ships. Insect prevalence was measured by calculating the percentage of the number of insects caught. The results of the research were processed descriptively to see a description of the location of vector infestations on passenger ships and cargo ships that docked at Bau-bau Harbor by looking at the characteristics of the ship based on the type of ship and the age of the ship. The results obtained that cockroaches are the vectors with the highest infestation on ships as many as 10 on passenger ships and 11 on cargo ships. The average age of ships that dock at Baubau port is quite old. Vessels > 7 years old have the most vector infestations and cockroaches are one of the most numerous types of vectors.
Keywords: Vector Infestation, Passenger Ship, Freight Ship
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Díaz Ojeda, Héctor Rubén, Sebastian Oyuela, Roberto Sosa, Alejandro Daniel Otero, and Francisco Pérez Arribas. "Fishing Vessel Bulbous Bow Hydrodynamics—A Numerical Reverse Design Approach." Journal of Marine Science and Engineering 12, no. 3 (February 29, 2024): 436. http://dx.doi.org/10.3390/jmse12030436.
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Naval hydrodynamics typically focus on reducing ship resistance, which can be achieved by incorporating a bulbous bow. This feature is commonly used in the merchant fleet and smaller vessels, such as fishing boats, to minimize wave-making resistance. However, it is important to note that the use of a bulbous bow may not always be necessary or effective in all ship designs. In some cases, fishing ship designs may include a bulbous bow that is not optimized due to the use of procedures and methods intended for larger merchant ships or based on past experience. This study examines the effect of different bow designs, including the bulbous bow, on ship resistance in calm water, with a focus on a typical Argentinian trawler fishing vessel. The objective of this research is to assess the hydrodynamics of various designs for a particular ship by modifying its vessel lines. Firstly, the bulbous bow is removed, and then the reduction in ship resistance achieved by the bulbous bow under different load conditions and speeds is evaluated by comparing the vessel with and without the bulbous bow. The numerical analysis is performed using OpenFOAM, and the results are validated through towing tank experiments. This research indicates that the performance of the bulbous bow varies under different conditions. Therefore, it is recommended to conduct an initial study and a full evaluation of the design and operation alternatives.