Vortex ring modelling of toroidal bubbles
Vortex ring modelling of toroidal bubbles
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DOI：
10.1007/s00162-005-0164-6
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发表时间：
2005-05
影响因子：
3.4
通讯作者：
Q. X. Wang;K. S. Yeo;B. Khoo;K. Lam
中科院分区：
文献类型：
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作者：
Q. X. Wang;K. S. Yeo;B. Khoo;K. Lam
在靠近表面的气泡破裂过程中，经常会形成高速液体射流，并随后撞击相反的气泡表面。喷流撞击将原来单一连接的气泡转变为环形气泡，并在其周围的流动中产生循环。通过在气泡环面内引入一个涡环来模拟环状气泡的环流。然后，速度势被分解为涡环的势和残余势。由于剩余势是连续的，并且满足拉普拉斯方程，因此可以用边界积分方法来模拟，从而避免了显式区域切割和相关的数值处理。应用该方法研究了刚性壁面附近气泡的坍塌问题。用区域切割法得到的结果与Best(J.Fluid Mech.25179-107,1993)的结果符合得很好。对射流撞击过程中壁面压力冲量的检测表明，高速液体射流很有可能对表面造成损害。在液体射流最具破坏性的地方，似乎存在一个最佳的初始距离。
During the collapse of a bubble near a surface, a high-speed liquid jet often forms and subsequently impacts upon the opposite bubble surface. The jet impact transforms the originally singly-connected bubble to a toroidal bubble, and generates circulation in the flow around it. A toroidal bubble simulation is presented by introducing a vortex ring seeded inside the bubble torus to account for the circulation. The velocity potential is then decomposed into the potential of the vortex ring and a remnant potential. Because the remnant potential is continuous and satisfies the Laplace equation, it can be modelled by the boundary-integral method, and this circumvents an explicit domain cut and associated numerical treatment. The method is applied to study the collapse of gas bubbles in the vicinity of a rigid wall. Good agreement is found with the results of Best (J. Fluid Mech.25179–107, 1993), obtained by a domain cut method. Examination of the pressure impulse on the wall during jet impact indicates that the high-speed liquid jet has a significant potential for causing damage to a surface. There appears to be an optimal initial distance where the liquid jet is most damaging.