浅水域中多船编队航行时的船波干涉

Wave Interactions Generated by Multi-Ship Unite Moving in Shallow Water

以Green-Naghdi(GN)方程为基础,采用波动方程和运动网格的有限元法研究多船在浅水域中集体航行时的波浪干涉特性。把运动船舶对水面的扰动作为移动压强直接加在GN方程里,以描述运动船体和水面的相互作用。GN方程合理地考虑非线性和频率散射对浅水船波的影响。以Series60 CB=0.6船体为算例,给出两船并行、前后跟随、三船品字形编队航行时的波浪干涉图形,波浪阻力及侧向力的数值分析结果。计算结果表明:1)当两船并行时,两船承受侧向吸引力,同时波浪阻力稍有增加。2)当两船前后跟随时,两船的波浪阻力都减小。3)当三船品字形航行时,前船的阻力减小,后船的阻力增加,同时后面两船的吸力减小。

Based on Green-Naghdi (G-N) equation, a Wave Equation Model (WEM) and Galerkin finite element method (FEM) with moving grids are combined to investigate the wave interactions generated by multi-ship moving in shallow water, where moving ships are regarded as moving pressure disturbances on free surface. The moving pressure is incorporated into the G-N equation to formulate the interactions of moving ships and free surface. G-N equation involves nonlinearity and frequency dispersion to account for the effects of finite water depth on ship waves. The numerical examples of Series 60(CB=0.6) ships moving in shallow water are presented. Three-dimensional ship wave profiles, wave resistances and transverse forces are given in three cases of two-ships parallelly moving, a ship moving followed by the other, and three-ships moving with a triangle feature. The numerical results indicate that the ships experience an attractive transverse force when two ships move in parallel, and the wave resistance slightly increases; the wave resistance of both ships decrease when a ship moves followed by the other; when three ships move as a triangle the resistance exerted on the leading ship decreases, but increases for the two following ships with weakened attractive transverse force.