二维水翼非定常空泡流数值模拟

对非稳态空泡流现象的研究已成为当今一个研究重点。空泡非稳态脱落及其内部流动结构越来越受到研究人员的关注,但对其研究目前仍主要依靠实验手段。发展有效的数值模拟方法研究相关的机理具有重要的意义。本文从RANS方程入手,采用状态方程空化模型和计及可压缩性的SIMPLEC算法,实现了二维水翼CAV2003非定常空泡流动的数值模拟。研究了空泡从初生、发展、断裂,以及最终空泡在下游高压区溃灭的整个过程。计算表明,回射流并非完全液相的,而是汽液两相的。近壁面的回射流是导致空泡脱落的主要原因。最后,通过与第五届国际空泡会议上发表的7篇文献的对比,发现本文的计算结果是合理的。

Numerical simulation of unsteady cavitating flows around a two-dimensional hydrofoil

The study of unsteady cavitating flows is one of the important topics in hydrodynamics research. The shedding of cavitating flows and the flow structures inside cavity have attracted great interest. Experimental method is still main way to treat the problem up to now,however,to develop numerical methods is strongly needed both in mechanism research and engineering application. In this paper from the RANS equations approach,the cavitation model based on the equation of state,the SIMPLEC algorithm modified to consider compressibility are adopted to simulate the unsteady cavitating flows. As an example unsteady cavitating flows around CAV2003 are calculated. The periodic process,which includes inception,development,break-off and finally shedding cavity collapsing at the high-pressure area downstream,is obtained. It is found that re-entrant jet is not absolutely constituted by liquid,but vapor/liquid mixture. The break-off process is directly induced by re-entrant jet closely along the wall. A comparison between the peer numerical results obtained by several authors in 5th International Symposium on Cavitation is also performed. It is found our numerical results can predict the unsteady phenomenon quite well.