不同曲率球面体入水砰击载荷数值计算
2016-10-12于龙超闫发锁赵九龙
于龙超,闫发锁,赵九龙,王 淇
(1.哈尔滨工程大学,黑龙江 哈尔滨 150001; 2.沪东中华造船(集团)有限公司,上海 200129)
不同曲率球面体入水砰击载荷数值计算
于龙超1,闫发锁1,赵九龙2,王 淇1
(1.哈尔滨工程大学,黑龙江 哈尔滨 150001; 2.沪东中华造船(集团)有限公司,上海 200129)
从三维边界元方法出发,基于Wagner的自由液面抬升理论,采用数值仿真的方法研究了圆球入水的问题。通过数值模拟与轴对称体入水试验结果的正确性及适用性进行验证的基础上,并分析了不同半径的球体在不同速度下的入水总体受力和表面压力的变化规律。计算结果表明随着球体半径和入水速度的增加,峰值压力迅速增加,受力峰值与球体半径的平方和入水速度平方成正比关系;球体表面压力系数的分布计算结果表明,在测试点与水开始接触时压力系数最大,然后迅速减小;压力系数和入水速度无关,但和入水深度相关。
球体砰击;边界元法;受力峰值;压力系数
Abstract:Based on Wagner’s theory,the numerical simulation by 3D BEM method was used to study the slamming problem of spheres with different curvatures.The numerical results were validated by the test data from an axisymmetric body slamming test[11].The force acting on the body and the pressure at 5 specified locations are analyzed for the spheres with different radiuses and entry speeds.The result shows that the peak pressure increases rapidly with the increase of the radius and velocity,and the peak pressure has a linear relationship with the square of the radius of sphere and velocity.To calculate the distribution of the pressure coefficient along the surface of the sphere,we selected some test points in the sphere at different angles.The result shows the pressure coefficient has the maximum value when the test point touches water,and then decreases rapidly,and the pressure coefficient is sensative to the entry depth.
Keywords:sphere water entry; BEM; peak pressure; pressure coefficient
结构物入水是一个瞬态过程,在砰击入水过程中会受到巨大的冲击载荷,甚至会导致结构物的破坏,因此砰击问题的研究对于入水结构物的设计具有重要意义。如船舶在恶劣海况中航行的时候,由于船舶的剧烈起伏运动,首尾会频繁的入水,入水过程中所产生的砰击压力会造成船体结构的局部变形,严重的会造成船舶结构的破坏。随着海洋军事和民用航海领域的不断发展,砰击问题广泛存在于救生艇的落放、宇宙飞船的海上回收、海上飞机的降落,以及空投鱼雷入水等研究领域之中。……
