水面舰船附近气泡运动数值模拟

当气泡在自由面和水面舰船附近运动时,两者的存在均会对气泡脉动产生影响。基于不可压缩势流理论,采用边界元方法对边界积分方程进行求解。针对建立自由面需要大量的网格,且处理自由面与水面结构交界面时数值不稳定,采用考虑自由面效应的格林函数取代基本格林函数,通过与自由面附近气泡轴对称模型的计算结果进行对比,验证了该方法的有效性。通过对舰船结构附近的气泡运动射流特性进行模拟,发现当药包在舷侧和自由面附近爆炸时,气泡射流可能不会完全作用在舰船上,自由面效应的存在削弱了气泡的打击能力。

Numerical Simulation of Underwater Explosion Bubble Near a Warship

When an underwater explosion occurs near both a free surface and a warship structure,the bub ble motion could be affected.In this paper,the boundary integral equation was solved by adopting the boundary element method（BEM）,based on the potential flow theory of incompressible liquid.To reduce the quantity of meshes required when modeling the free surface and to deal with the instability of solid-free surface interfaces,a Green function considering the free surface effect was adopt to replace the fundamen tal Green function.This numerical method was validated by comparing the above mentioned model with an axisymmetrical model.Also,the bubble motions as well as its jet feature near a warship structure and a free surface were simulated,and it was found out that the bubble jet would not significantly impact the war ship structure because of the free surface effect.