基于流固耦合航行体入水冲击数值模拟研究

Research on Numerical Simulation of Water-Entry Impact Based on Fluid-Structure Coupling

针对航行体入水冲击过程中的流固耦合问题,利用任意拉格朗日-欧拉算法建立三维入水冲击数值仿真模型。首先,建立球体入水冲击数值模型,获取了入水过程中的冲击载荷和表面压力数据,通过与试验对比,探究网格密度、接触刚度耦合系数以及时间步长对仿真准确性的影响。结果发现,冲击区域网格密度和接触刚度耦合系数决定流固耦合接触刚度;冲击域的网状密度对冲击系数结果和入水速度变化有明显影响;耦合节点之间的接触刚度系数会影响局部压力峰值。最后,建立锥形头部圆柱体入水仿真模型,提出分段刚体计算截面载荷方法,研究不同速度下结构入水冲击加速度、速度、位移和截面载荷变化规律,与试验结果对比证明仿真准确性。

Aiming at the fluid-structure coupling problem in the process of water-entry impact, a three-dimensional numerical simulation model is established by using arbitrary Lagrange-Euler method. Firstly, the numerical model of spherical is established, and the impact load and surface pressure of water-entry are obtained. By comparing with the test, the effects of grid density, contact stiffness coupling coefficient on the simulation accuracyare explored. The result show that the mesh density of the impact domain is very important to the quality of the simulation results. The contact stiffness between the coupling nodes affects the local peak pressure values. Finally, the water-entry simulation model of a conical head cylinder is established and the piecewise rigid body calculation is proposed. The acceleration, velocity, displacement and section load at different speeds are studied. Comparing with the test results, the accuracy of damage is proved.