Purpose

Understanding the interaction of turbulence and cavitation is an essential step towards better controlling the cavitation phenomenon. The purpose of this paper is to bring out the efficacy of different modelling approaches to predict turbulence and cavitation-induced phase changes.

Design/methodology/approach

This paper compares the dynamic cavitation (DCM) and Schnerr–Sauer models. Also, the effects of different modelling methods for turbulence, unsteady Reynolds-averaged Navier–Stokes (URANS) and detached eddy simulations (DES) are also brought out. Numerical predictions of internal flow through a venturi are compared with experimental results from the literature.

Findings

The improved predictive capability of cavitating structures by DCM is brought out clearly. The temporal variation of the cavity size and velocity illustrates the involvement of re-entrant jet in cavity shedding. From the vapour fraction contours and the attached cavity length, it is found that the formation of the re-entrant jet is stronger in DES results compared with that by URANS. Variation of pressure, velocity, void fraction and the mass transfer rate at cavity shedding and collapse regions are presented. Wavelet analysis is used to capture the shedding frequency and also the corresponding occurrence of features of cavity collapse.

Originality/value

Based on the performance, computational time and resource requirements, this paper shows that the combination of DES and DCM is the most suitable option for predicting turbulent-cavitating flows.

中文翻译：

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使用动态空化模型预测非定常内部湍流空化流

目的

了解湍流和空化的相互作用是更好地控制空化现象的重要一步。本文的目的是展示不同建模方法在预测湍流和空化引起的相变方面的功效。

设计/方法/方法

本文比较了动态空化 (DCM) 和 Schnerr-Sauer 模型。此外，还提出了不同建模方法对湍流、非定常雷诺平均纳维-斯托克斯 (URANS) 和分离涡模拟 (DES) 的影响。通过文丘里管的内部流动的数值预测与文献中的实验结果进行了比较。

发现

清楚地展示了DCM对空化结构的改进预测能力。空腔尺寸和速度的时间变化说明了折返射流参与空腔脱落。从蒸汽分数等高线和附着的空腔长度可以看出，与 URANS 相比，DES 结果中重入射流的形成更强。给出了空腔脱落和塌陷区域的压力、速度、空隙率和传质速率的变化。小波分析用于捕捉脱落频率以及相应出现的空腔塌陷特征。

原创性/价值

基于性能、计算时间和资源要求，本文表明 DES 和 DCM 的组合是预测湍流空化流的最合适的选择。