Parametric automatic optimal design of USV hull form with respect to wave resistance and seakeeping

2021 ◽  
Vol 235 ◽  
pp. 109462
Author(s):  
Guan Guan ◽  
Lei Wang ◽  
Jiahong Geng ◽  
Zhengmao Zhuang ◽  
Qu Yang
Keyword(s):  
Optimal Design ◽  
Wave Resistance ◽  
Hull Form

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.

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.

Hull Form Optimization by Shift and Deformation of Ship Sections

2001 ◽  
Vol 45 (03) ◽  
pp. 197-204
Author(s):  
N. E. Markov ◽  
K. Suzuki
Keyword(s):  
Optimization Procedure ◽  
Longitudinal Direction ◽  
Wave Resistance ◽  
Test Case ◽  
Hull Form ◽  
B Spline ◽  
Specific Change ◽  
Rankine Source ◽  
Form Design ◽  
Hull Form Design

A technique for reducing ship wave resistance is presented. It is based on a single B-spline patch which approximates the hull surface. A selected specific change of the B-spline coefficients resembles a smooth shift of the ship sections in the longitudinal direction. An unconstrained Davidson-Fletcher-Powell (DFP) optimization procedure controls the changes. The wave resistance is evaluated by a higher-order Rankine source panel method. The numerical results, shown for Series 60 and the Hamburg Test Case (HTC) containership, prove that the method is appropriate for preliminary hull form design.

Zero wave resistance for ships moving in shallow channels at supercritical speeds

1997 ◽  
Vol 335 ◽  
pp. 305-321 ◽  
Author(s):  
XUE-NONG CHEN ◽  
SOM DEO SHARMA
Keyword(s):  
Shallow Water ◽  
Water Channel ◽  
Wave Theory ◽  
Wave Pattern ◽  
Wave Resistance ◽  
Kp Equation ◽  
Nonlinear Case ◽  
Hull Form ◽  
Ship Waves ◽  
Shallow Channel

This paper deals with the wave pattern and wave resistance of a slender ship moving steadily at supercritical speed in a shallow water channel. Using, successively, linear and nonlinear shallow-water wave theory it is demonstrated that, if the hull form is adapted to speed and channel geometry according to certain rules, the ship waves can be made to form a localized pattern around the ship that moves at the same speed as the ship and at the same time the associated wave resistance can be made to vanish. In the nonlinear case, the zero-wave-resistance ship hull is derived from a KP equation solution of the oblique interaction of two identical solitons. This astonishing phenomenon may be called shallow-channel superconductivity.

Potential of Michell’s Integral for Ship Wave Resistance

2014 ◽  
Author(s):  
Takashi Tsubogo
Keyword(s):  
Integral Equation ◽  
Froude Number ◽  
Computing Time ◽  
Wave Resistance ◽  
Boundary Integral ◽  
Hull Form ◽  
Number Range ◽  
Gradient Effect ◽  
Depth Direction ◽  
Wigley Hull

The Michell’s integral (Michell 1898) for the wave making resistance of a thin ship has not been used widely in practice, since its accuracy is questioned especially for a Froude number range about 0.2 to 0.35 for conventional ships. We examine calculations by Michell’s integral for some ship forms, e.g. a parabolic strut, Wigley hull and so on. As a result, one reason of the disagreement with experiments is revealed. It must be the gradient of hull form in the depth direction. Then a thin ship theory including the hull gradient effect in the depth direction is presented, which improves slightly in low Froude numbers but needs more computing time than Michell’s integral so as to solve a boundary integral equation.

scholarly journals Influence of the transom immersion to ship resistance components at low and medium speeds

2020 ◽  
Vol 17 (2) ◽  
pp. 165-182
Author(s):  
I. Z. Mustaffa Kamal ◽  
A. Imran Ismail ◽  
M. Naim Abdullah ◽  
Y. Adnan Ahmed
Keyword(s):  
Froude Number ◽  
Wave Resistance ◽  
Hull Form ◽  
Ship Resistance ◽  
Resistance Components ◽  
Ranse Solver

The transom stern offered some advantages over the traditional rounded cruiser stern reducing the resistance of a ship. This can only be achieved if the transom stern is carefully designed with suitable transom immersion ratio. In this study, the influence of different transom area immersion ratios on the resistance components was investigated for a semi-displacement hull and a full displacement hull.  The base hull was based on NPL hull form and KCS hull form for a semi-displacement and full-displacement hull respectively. The transom immersion ratios for the NPL hull were varied at a ratio of 0.5, 0.7, 0.8 and 1.0.  The resistance of each of the NPL hull form was simulated at Froude number 0.3 up to 0.6. The transom immersion ratios for the KCS hull were varied at a ratio of 0.05, 0.1, 0.15 and 0.3. The resistance of each of the KCS hull form was simulated at Froude number 0.195, 0.23, 0.26 and 0.28.  The transoms of both hulls were modified or varied systematically to study the influence of the transom shape or immersion on the total and wave resistance components. The investigation was carried out using a CFD software named SHIPFLOW 6.3 based on RANSE solver. These results on the NPL hull shows that the larger the transom immersion, the higher the resistance will be for a semi-displacement vessel. The increased resistance is contributed by additional frictional and wave resistance components. The results for the KCS hull seems to contradict with the results obtained from the NPL hull. The larger and deeper transom for the case of KCS hull form sometimes can be beneficial at higher Froude number.

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