水面平板下方非球状爆炸气泡运动数值模拟

Numerical simulation of non-spherical explosion bubble motion below plate floating on water

基于势流假设,采用线性三角形单元直接边界元法对气泡外的水流流场进行计算,并采用二阶龙格-库塔法追踪气泡形状变化。同时,为了保证数值计算稳定,采用弹性网格技术对气泡表面网格进行光滑处理,并对近距离情况水下爆炸进行了计算,得到了气泡外形和作用于平板表面上压强随时间变化的规律。将计算结果与已有结果进行了比较分析,两者吻合较好,证明了该计算方法和计算程序的可信性。

Based on potential flow hypothesis, the direct boundary element method of linear triangle ele- ment is used to calculate the water flow field around the bubble below the plate, and the second-order Runge-Kutta method is adopted to keep track of the change in bubble shape. Impinging jet is modeled by the vortex ring when the cap-like bubble is transferred to toroidal bubble. To ensure the stability of numerical calculation, the elastic mesh technique （EMT） is used to smooth the bubble surface mesh. By simulating the ratio of small explosion depth to maximum bubble radius, both the bubble shape and the pressure distribution on the plate at different time are obtained. The computed results are in good agreement with the existing results, which proves the calculating method and procedure to be effective.