轴对称体砰击载荷的三维动网格数值计算

Numerical Calculation of t Slamming Load for Axisymmetric Geometries Using 3D Dynamic Mesh

基于三维边界元方法研究了三维轴对称体入水砰击载荷的数值算法。算法从三维力学模型出发，继承了Wag—ner自由液面抬升理论，引入浸深因子Cw以确定自由液面抬升高度，并且将自由液面线性化处理，同时考虑网格运动，在自由液面附近对网格进行截断重构，以确保水下湿面积的精准。算法中使用考虑加权运动项的非线性伯努利方程计算得到入水结构的表面压力，进一步积分可得入水结构的总体受力。此外，文中分别通过Nisewanger的圆球入水试验与Alaoui的圆锥入水试验对算法的正确性及适用性进行了验证。

A numerical method for prediction of the slamming load from axisymmetric geometries based on 3D BEM was introduced in this paper. The hydrodynamic model based on Wagner＇s theory were utilyzed in the numerical code, which considers the rising of free water surface during impact. In the method, wetting factor Cw was introduced to ensure the exact height of the uplift free surface. At the same time the grid＇s movement was also considered here and along the interface between the geometry and the free surface one group of grids were modified for a precise wet area. The Nonlinear Bernoulli equation considering the grid＇s movement is used for calculating the hydrodynamic pressure and the force could be got through integration. Results from slamming test for 3D bodies in reference [10] and [-15] were introduced to prove validity of the menthod.