Numerical modelling and investigation of symmetric and asymmetric cavitation bubble dynamics
Numerical modelling and investigation of symmetric and asymmetric cavitation bubble dynamics
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DOI：
10.1016/j.compfluid.2012.07.020
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发表时间：
2012-10-30
影响因子：
2.8
通讯作者：
Adams, N. A.
中科院分区：
文献类型：
--
作者：
Lauer, E.;Hu, X. Y.;Adams, N. A.
在本文中，我们研究了高速动力学的对称和非对称空泡溃灭。为了这个目的，采用了一个尖锐的界面数值模型，其中包括一个数值有效的蒸发/冷凝模型。基本的假设是，相变发生在热非平衡和相关的时间尺度是远远大于由界面黎曼问题所描述的波动力学。尖锐的接口模型允许一个准确的跟踪整个崩溃和反弹的接口演变。与第一组模拟，我们调查的非平衡振荡蒸汽泡的松弛行为的影响。我们观察到，一个很好的预测的相变速率是必不可少的。具有高度实际意义的是在高环境压力条件下壁附近气穴气泡的破裂。我们研究了分离和附着的气泡在坍缩演化中的差异。结果表明，最大壁压强烈依赖于对称性的崩溃机制，和区域的气泡反弹的概率高。不对称的附着气泡导致显着不同的拓扑结构的变化过程中崩溃比对称的气泡，但表现出大致相同的范围内的最大压力。(C)2012爱思唯尔有限公司保留所有权利。
In this paper, we investigate the high-speed dynamics of symmetric and asymmetric cavitation bubble-collapse. For this purpose, a sharp-interface numerical model is employed, that includes a numerically efficient evaporation/condensation model. The underlying assumption is that phase change occurs in thermal non-equilibrium and that the associated timescale is much larger than that of the wave-dynamics described by the interfacial Riemann problem. The sharp-interface model allows for an accurate tracking of the interface evolution throughout collapse and rebound. With a first set of simulations, we investigate the influence of the non-equilibrium on the relaxation behaviour of an oscillating vapour bubble. We observe that a good prediction of the phase-change rate is essential. Of high practical interest is the collapse of cavitation bubbles near walls under high ambient-pressure conditions. We investigate the differences in collapse evolution for detached and attached bubbles. It is shown that the maximum wall pressure strongly depends on the symmetry of the collapse mechanisms, and regions with a high probability of bubble rebound are identified. Asymmetric attached bubbles lead to significantly different topology changes during collapse than symmetric bubbles but exhibit roughly the same range of maximum pressures. (C) 2012 Elsevier Ltd. All rights reserved.