Study on Hull Form Optimization for Minimum Resistance Based on Niche Genetic Algorithms

2011 ◽  
Vol 27 (4) ◽  
pp. 162-168 ◽  
Author(s):  
Zhang Bao-ji ◽  
Ma Kun
Keyword(s):  
Genetic Algorithms ◽  
Hull Form ◽  
Niche Genetic Algorithms ◽  
Minimum Resistance

Study on Hull Form Optimization for Minimum Resistance Based on Niche Genetic Algorithms

2011 ◽  
Vol 27 (04) ◽  
pp. 162-168
Author(s):  
Zhang Bao-ji ◽  
Ma Kun
Keyword(s):  
Genetic Algorithms ◽  
Optimization Design ◽  
Rapid Convergence ◽  
Hull Form ◽  
Rankine Source ◽  
Design Variables ◽  
The Individual ◽  
Niche Genetic Algorithms ◽  
Basic Constraint ◽  
Minimum Resistance

The Niche Genetic Algorithms (NGAs) can overcome the deficiency of Genetic Algo-rithms (GAs), such as premature convergence and low ability of local search. The NGA can maintain the diversity of the individual in groups. Meanwhile, it has a high ability of globally searching and a rapid convergence rate. To get the hull form with minimum resistance, an optimization design of the hull form with NGA method, which is combined with CAD technology based on the Rankine source method, is proposed. The total resistance is taken as objective function in the optimization process, study on the optimization of the fore-body of hull is proposed, with the parameter of hull form modification function as design variables, with an appropriate displacement as the basic constraint. Initially, the Series60 hull was selected as the base for the optimized calculation. Comparison between the optimized results of the NGAs and GAs shows that the hull based on the optimized NGA are valid and effective.

Optimized Analysis of the Hollow Floor Based on the Niche Genetic Algorithms

2013 ◽  
Vol 421 ◽  
pp. 751-755
Author(s):  
Chuan Teng Huang ◽  
Zhi Jun Wang
Keyword(s):  
Genetic Algorithms ◽  
Optimal Solution ◽  
Threshold Value ◽  
Geometric Parameters ◽  
Optimization Analysis ◽  
Global Optimal Solution ◽  
Excellent Mechanical Property ◽  
Section Design ◽  
Global Optimal ◽  
Niche Genetic Algorithms

Nowadays, the hollow floor is widely used due to its excellent mechanical property and economic benefit.However, its related specification is absence of evaluation in geometric parameters. The optimized analysis aimed at the hollow floor under vertical load, the total cost of the hollow floor is considered as a objective function, the maximum deflection and the threshold value of the geometric parameters are considered as constrain conditions. The program, which introduces the section design and compiled by the python script, based on the niche genetic algorithms is used to analyze the optimization of a hollow floor. Comparing to the global optimal solution, the program achieves good results. It indicates that the niche genetic algorithms is efficient and suited for the optimization analysis of hollow floor. The above mentioned conclusions will be conducive to engineering design and further research in this field.

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.

The Design of an Eight-Oared Rowing Shell

1993 ◽  
Vol 30 (02) ◽  
pp. 84-99
Author(s):  
Carl A. Scragg ◽  
Bruce D. Nelson
Keyword(s):  
Shallow Water ◽  
High Speed ◽  
Hull Form ◽  
Model Scale ◽  
Minimum Drag ◽  
Final Design ◽  
Minimum Displacement ◽  
Resistance Curves ◽  
Hull Forms ◽  
Minimum Resistance

Rules governing the design of rowing shells do not restrict basic hull parameters. In designing a new eight-oared rowing shell for international ard Olympic competition, the authors sought a high speed, minimum drag hull form, subject only to the constraints on minimum displacement and roll stability. An investigation of optimum hull parameters using analytically determined resistance curves was made. Optimum hull parameters for both deep and shallow water racing are presented. Using the hull parameters determined for minimum resistance at racing speeds in shallow water, several new hull forms were created and analyzed in both deep and shallow water. Two promising final design candidates were proposed for model-scale testing. Results of both steady and unsteady towing tests are presented.

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