scholarly journals Optimization Design of Minimum Total Resistance Hull Form Based on CFD Method

2018 ◽  
Vol 32 (3) ◽  
pp. 323-330 ◽  
Author(s):  
Bao-ji Zhang ◽  
Sheng-long Zhang ◽  
Hui Zhang
Keyword(s):  
Optimization Design ◽  
Total Resistance ◽  
Hull Form ◽  
Cfd Method

Bow and Stern Shape Integrated Optimization for a Full Ship by a Simulation-based Design Technique

2014 ◽  
Vol 58 (02) ◽  
pp. 83-96 ◽  
Author(s):  
Sheng-Zhong Li ◽  
Feng Zhao ◽  
Qi-Jun Ni
Keyword(s):  
Optimization Design ◽  
Fluid Dynamic ◽  
Optimization Algorithms ◽  
Navier Stokes ◽  
Total Resistance ◽  
Hull Form ◽  
Wake Field ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Saving Effect

Advanced computational fluid dynamic (CFD) techniques and optimization algorithms are successfully integrated together into what is known as Simulation-based Design (SBD) techniques, which open a new situation for hull-form optimization design and configuration innovation. In this article, fundamental elements of the SBD techniques are described and crucial components are analyzed profoundly with a focus on breaking through key technologies as global optimization algorithms, hull geometry modification and reconstruction, and code integration. Then, combined with high-fidelity CFD codes (on Reynolds-averaged Navier-Stokes), an automatic hull-form design optimization framework is established. Based on that, the full ship (bulk carrier) is optimized by selecting the total resistance and the quality of propeller disk wake field as objective functions. The results show that the decrease of the total resistance is significant at the possible speed range with a reduction of approximately 5% taking into account gains of propulsion efficiency produced by the improvement of wake field, the comprehensive energy-saving effect will be further expanded. The example confirms the applicability of the developed SBD frame-work to the full ship design problems.

The Minimum Wave Resistance of Hull Form Design Method Based on CFD Method

2019 ◽  
Author(s):  
Bao-Ji Zhang ◽  
Chi Zhang ◽  
Wen-Xuan She
Keyword(s):  
Computer Aided Design ◽  
Optimization Design ◽  
Search Algorithm ◽  
Design Method ◽  
Three Dimensional ◽  
Wave Resistance ◽  
Hull Form ◽  
Design Variables ◽  
Cfd Method ◽  
Green Ship

To reduce the resistance of the ship in actual navigation, a hull form optimization design method for minimum wave resistance is proposed. A numerical wave tank of regular waves is established based on the CFD (Computational Fluid Dynamics) theory. Overlapping grid technology is adopted to mesh the hull form and free surface. The new hull offsets are generated by using the parameters of modified function as design variables. The geometric expression and reconstruction of optimized hull form is determined through the three-dimensional CAD (Computer Aided Design) modeling technology. The displacement limit was used as the basic constraint, and other additional constraints were considered; nonlinear programming quadratic line search algorithm was used to set up a mathematical model of hull form optimization on the ISIGHT platform. The optimization calculations of Wigley hull form and surface ship DTMB5415 are carried out. Compared with the parent hull, the wave resistance of the optimized hull form is significantly reduced, and the feasibility of this method is confirmed. The research results can provide technical support for the development of “green ship” design.

Development and Assessment of a Total Resistance Optimized Bow for the AE 36

1994 ◽  
Vol 31 (02) ◽  
pp. 149-160
Author(s):  
Donald C. Wyatt ◽  
Peter A. Chang
Keyword(s):  
Experimental Data ◽  
Optimization Procedure ◽  
Wave Resistance ◽  
Scale Model ◽  
Optimization Approach ◽  
Nonlinear Constraints ◽  
Total Resistance ◽  
Hull Form ◽  
Final Design ◽  
Resistance Data

A numerically optimized bow design is developed to reduce the total resistance of a 23 000 ton ammunition ship (AE 36) at a speed of 22 knots. An optimization approach using slender-ship theory for the prediction of wave resistance is developed and applied. The new optimization procedure is an improvement over previous optimization methodologies in that it allows the use of nonlinear constraints which assure that the final design remains within practical limits from construction and operational perspectives. Analytic predictions indicate that the AE 36 optimized with this procedure will achieve a 40% reduction in wave resistance and a 33% reduction in total resistance at 22 knots relative to a Kracht elliptical bulb bow design. The optimization success is assessed by the analysis of 25th scale model resistance data collected at the David Taylor Research Center deepwater towing basin. The experimental data indicate that the optimized hull form yields a 51% reduction in wave resistance and a 12% reduction in total resistance for the vessel at 22 knots relative to the Kracht bulb bow design. Similarly encouraging results are also observed when comparisons are made with data collected on two other conventionally designed AE 36 designs.

Valve Plate for Piston Pump Cavitation Problem with the Damp Groove Structural Optimization

2014 ◽  
Vol 543-547 ◽  
pp. 154-157 ◽  
Author(s):  
Wei Liu ◽  
An Lin Wang ◽  
Xue Wen Shan ◽  
Xiao Lu Zhang ◽  
Tao Jiang
Keyword(s):  
Optimization Design ◽  
Design Method ◽  
Structural Parameters ◽  
Structure Design ◽  
Valve Plate ◽  
Piston Pump ◽  
Cavitation Performance ◽  
Groove Structure ◽  
Cfd Method ◽  
Rsm Model

To reduce the cavitation occurring on valve plate of typical Swashplate piston pump, an optimization design method was introduced to quantitively analyse the accurate relationship between structural jet grooves parameters and cavitation.Using the CFD method, the sunking and discharging process in piston pump was simulated dynamically.The damp grooves structure effect on both jet angle and pressure shock were analysed visually with a series of different parametrical grooves.By establishing parametrical damp groove model, the piston pumps dynamic analysis was integrated with the technologies of CFD analysis, experimental design and approximation model, etc.The mathematical model of plunger pressure in oil back period, jet angle and structural parameters of damp groove were established in the form of second-order RSM model. The damp groove structure of valve plate was optimized on the basis of the RSM model.Test data show that the anti-cavitation performance of optimized valve plate was increased obviouslyAnd this method provided theoretical foundation for the structure design of damp groove.

scholarly journals Research on Ship Hull Optimisation of High-Speed Ship Based on Viscous Flow/Potential Flow Theory

2020 ◽  
Vol 27 (1) ◽  
pp. 18-28
Author(s):  
Zhang Baoji
Keyword(s):  
High Speed ◽  
Design Method ◽  
Frictional Resistance ◽  
Linear Wave ◽  
Total Resistance ◽  
Friction Resistance ◽  
Resistance Reduction ◽  
Before And After ◽  
Reduction Effect ◽  
Cfd Method

AbstractIn order to quickly obtain practical ship forms with good resistance performance, based on the linear wave-making resistance theory, the optimal design method of ship forms with minimum total resistance is discussed by using the non-linear programming (NLP) method. Taking the total resistance as the objective function (the Michell integral is used to calculate the wave-making resistance and the equivalent plate friction resistance formula is used to calculate the frictional resistance), the hull surface offset as the design variable and appropriate displacement as the basic constraints, and considering the additional constraints, the hull bow shape and the whole ship are optimised, and an improved hull form is obtained. The resistance of the ship before and after optimisation is calculated by the CFD method to further evaluate the resistance reduction effect and performance after optimisation. Finally, an example of optimisation calculation of an actual high-speed ship is given. The obvious resistance reduction results confirm the reliability of the optimisation design method.

scholarly journals Research on a method of hull form design based on wave-making resistance optimization

2012 ◽  
Vol 19 (3) ◽  
pp. 16-25 ◽  
Author(s):  
Jianglong Sun ◽  
Xujian Lv ◽  
Weibin Liu ◽  
Hanwen Ning ◽  
Xianwen Chen
Keyword(s):  
Cross Section ◽  
Frictional Resistance ◽  
Wave Resistance ◽  
Total Resistance ◽  
Hull Form ◽  
Mathematical Procedure ◽  
Result Show ◽  
Form Design ◽  
Hull Form Design ◽  
Resistance Performance

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.

scholarly journals Application of Basis Functions for Hull Form Surface Modification

2021 ◽  
Vol 9 (9) ◽  
pp. 1005
Author(s):  
Baiwei Feng ◽  
Chengsheng Zhan ◽  
Zuyuan Liu ◽  
Xide Cheng ◽  
Haichao Chang
Keyword(s):  
Surface Modification ◽  
Resistance Coefficient ◽  
Original Model ◽  
Basis Functions ◽  
Engineering Practice ◽  
Total Resistance ◽  
Hull Form ◽  
Modification Method ◽  
Selection Of

Basis functions are key in constructing interpolation equations in hull surface modification based on radial basis functions (RBF) interpolation. However, few have studied the selection of basis functions in depth. By comparing several typical basis functions through a theoretical analysis and two-dimensional modification examples, the Wendland ψ3,1 (W) function is selected. The advantages of hull form surface modification based on W function interpolation are further validated through a case study. Finally, the modification method is used to optimize a trimaran model. An optimal hull form with fair lines is obtained, and its wave-making resistance coefficient and total resistance are reduced by 8.3% and 3.8%, respectively, compared to those of the original model. These findings not only further illustrate that the W function is relatively suitable for hull form surface modification, but also validate the feasibility and value of the RBF interpolation-based surface modification method in engineering practice.

ON THE MACRO HYDRODYNAMIC DESIGN OF HIGHLY EFFICIENT MEDIUM- SPEED CATAMARANS WITH MINIMUM RESISTANCE

2021 ◽  
Vol 154 (A3) ◽  
Author(s):  
M Haase ◽  
J Binns ◽  
G Thomas ◽  
N Bose ◽  
G Davidson ◽  
...  
Keyword(s):  
High Speed ◽  
Preliminary Design ◽  
Total Resistance ◽  
Hull Form ◽  
Transport Efficiency ◽  
New Class ◽  
Highly Efficient ◽  
Medium Speed ◽  
Resistance Curves ◽  
Minimum Resistance

A new class of fuel-efficient and environmentally friendly twin-hull vessels is currently under development. Compared to high-speed catamarans, a significant reduction in speed combined with an increase in deadweight tonnes will lead to a highly efficient medium-speed catamaran design. Recently-built conventional and high-speed ferries are compared to each other in terms of length, speed, deadweight and transport efficiency to classify the new design. The goal of this study is to find a preliminary macro design point for minimum total resistance by considering the main particulars of the catamaran vessel: block coefficient, prismatic coefficient and slenderness and separation ratios of the demihulls. Publications containing recommendations towards the optimum hull form parameters for moderate Froude numbers are reviewed and existing experimental data analysed to identify parameters for this new class of vessel. Designs with varied L/BOA-ratios and constant deck area are compared to find configurations of low total resistance for carrying a nominated deadweight at a particular speed, the associated change of the light ship weight has been taken into account. Two different model test series of catamaran models have been considered and their resistance curves agreed to each other. Recommendations are made; with the most important being the vessel should not exceed a speed of Fr = 0.35, with optimal prismatic coefficients around CP ≈ 0.5 and low transom immersion. This study presents the preliminary design of medium-speed single and twin-hull vessels for operations close to hump speed.

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