Fast free2surface mesh generation for the calculation of tr imaran wave mak ing resistance

Transcription

1 31 4 Vol Journal of Harbin Engineering University Ap r doi: / j. issn , 1, 2 (1., ; 2., ) : Rankine, NURBS ( B ),,.,,,, Rankine. : ; ; ; B ; : U : A : (2010) Fast free2surface mesh generation for the calculation of tr imaran wave mak ing resistance WANG Zhong 1, LU Xiao2p ing 1, WANG W ei 2 ( 1. College of Ship and Power Engineering, Naval University of Engineering, W uhan , China; 2. Naval Academy of A rma2 ment, Beijing , China) Abstract: To generate a free2surface mesh quickly for trimaran wave making p roblem s that are being solved with the three2dimensional Rankine source method, a fast free2surface m esh generation system was developed. The water lines of the tramaran hulls and the boundaries of the free2surface domain were exp ressed by NURB S curves. U sing the methods and software p resented, a free2surface m esh was generated quickly. and significantly reduced control parameters. It required only the waterline offset U sing commercial software to generate such a mesh would require much greater effort. W ith the method p resented, a free2surface mesh for the trim aran both w ith and w ithout a tran2 som stern could be generated very quickly. ance w ith the Rankine source method. This enhanced efficiency when calculating trimaran wave m aking resist2 Keywords:wave making resistance; panel method; trim aran; NURBS; free2surface mesh Rankine,, [ 1 ]. [ 224 ].,. Dawson, ;,, Dawson : : (9140A306JB11). : ( 19812),,, E2mail: wangzhonghj@ sina. com; (19572),,,. :., Rankine.,, [ 526 ].,., ( Gambit ICEM ),,.,,.

2 , 1,.,,, ;,, 3.., 1 2 : ( ) D y D x P 1 P 12 P 13 P 2 P 1 P 11 P 11 P 1 P 8, L. NURBS : l 1 l 2 l 3 l 4 l 5 l 6 l 7 l 8 l 9, 2. NURBS, 2, NURBS, S 1 S 5 5,. NURBS ( ),,.,. Rankine,, ( ), ( )., l 4, l 4 S 3, NURBS, k N, u [0, 1 ] k N, u 0 u 1 u 2 u N NURBS P ( u i ),, 3. 1 Fig. 1 W indow of the software 3 NURBS 2 Fig. 2 Free2surface mesh parameter definition 2, : P 1 P 2 P 3 P 4 P 5 P 6 P 7 P 8 P 9 P 10. Fig. 3 NURBS curve subsection i : u i = u i - u i- 1 = ak i- 1, i = 1, 2,, N. i =N 6 i =N u i = 6 ak i- 1 = i =1 i =1

3 4, : 411 (1) 1 - k N a = 1. (1) 1 - k a = 1 - k 1 - k N. (2) ( ) ( b) t, 1, 30, 30, 8, 45, 1. 1, 3, 2, , ;,,. 3 5 Fig. 5 Free2surface mesh examp les 4 Fig. 4 Flow chart of free2surface mesh generation,,,,. 2 5, 5 ( a), 1, 20, 20, 1. 07, 2, W igley [ 8 ],. W igley y = B 2 [ 1 - ( x L /2 ) 2 ] [ 1 - ( z T ) 2 ]. (3) : L /B = 10, B / T = 1. 6,.,, Dawson,,,, : L, 0. 2 L., ( ) [ - L, 2L ], [ 0, L ], 0. 5 L, 1. 5 L, L.,

4 412 31, Dawson,,., L 38. y, 6, y. y y, 7., 38, 19, : x = y = 5 5x = 5 x x 5 5 5y = 5 y y 5 y, x = - x, y = - y x. (5) (6) 3,, 2., 7 [ ]. 6 Fig. 6 Stream line free2surface mesh,, 0, ( x ), 6 ; 45, 1,, 38, 38, 7, 1. 0.,. 7 [ 8 ]. [ 9 ] 6 ; 0 45,,, (, ) ( x, y) : = ( x, y), = ( x, y). (4) 7 Fig. 7 W ave drag comparison between the calculated results and experimental results 7,, Rankine,,,,,. 0,,.,,

5 4, : 413,. 45 0, 45, 45. 4,,,,. W igley,.,.,. : [ 1 ],. Dawson [ J ]., 2000, 18 (1) : GAO B in, M IAO Guop ing. Investigation of grid generation in Dawson method [ J ]. Ocean Engineering, 2000, 18 ( 1) : [ 2 ] SAUNDERS J R P. An investigation of the resistance p rop2 erties of a modern trimaran combatant ship base on Taylor standard series and series64 [ D ]. School, 1995: 129. CA: naval Postgraduate [ 3 ],. [ J ]. (A ), 2004, 19 ( 3 ) : LU Xiaop ing, PAN Yucun. An investigation of wave resistance on the high speed trimarans and their p iece hull position op tim ization [ J ]. Journal of Hydrodynam ics ( Ser A), 2004, 19 (3) : [ 4 ] WANG Hu, ZOU Zaojian. Numerical research on wave2 making resistance of trimaran [ J ]. J Shanghai J iao Tong University, 2008, 13 (3) : [ 5 ]. [M ]. :, 2003: [ 6 ],,. / [ J ]., 2006, 10 (2) : CHEN J ingpu, ZHU Dexiang, HE Shulong. Research on nu2 merical p rediction method for wave making resistance of cat2 amaran / trimaran[ J ]. Journal of Ship Mechanics, 2006, 10 (2) : [ 7 ]. B [M ]. :, 2001: [ 8 ]BATTISTIN D, DAN IELL IA, ZOTTI I. Numerical and ex2 perimental investigations on wave resistance of trimaran con2 gurations [ C ] / / Proceedings of the 9 th International Mari2 time A ssociation of Mediterranean. Ischia, Italy, [ 9 ] DAW SON C W. A p ractical computer method for solving ship wave p roblem s [ C ] / /Proc of 2nd Intl Conf on Num Ship Hydrodyn. Berkeley, Calif, [ 10 ],,. [ J ]., 2009, 30 (6) : WANG Zhong, LU Xiaop ing, ZHONG Shigang. M ulti2hull ship wave making resistance calculation based on Kochin function integral analysis exp ression on the surface panels [ J ]. Journal of Harbin Engineering University, 2009, 30 (6) : [ 11 ] PENG Hongxuan. Numerical computation of multi2hull ship resistance and motion [ D ]. Halifax Dalhousie Uni2 versity, 2001: [ : ]