Numerical prediction of interaction between turbulence structures and vortex cavitation

ABSTRACT

A novel numerical method to perform direct numerical simulations (DNS) of turbulent flow was established to predict the characteristics of compressible gas–liquid two-phase flow. A cavitation model was introduced to reproduce the phase change in the cavitation phenomena, and a DNS of wall turbulence of water with cavitation was performed. Vortex cavitation was observed in the wall turbulence. The growing cavity in the core of the vortex changed the vortex intensity. After vortex cavitation finished, the friction coefficient for the cavitating flow became lower than that of non-cavitating flow. The variation tendency of turbulent statistics corresponded to that of experimental measurements. For a small friction coefficient of the cavitating flow, the redistribution term in the streamwise component of the turbulent kinetic energy equation was reduced owing to the vortex cavitation. Consequently, it was proved that the occurrence of vortex cavitation modified the redistribution term, resulting in turbulence modification.

KEYWORDS:

• Vortex cavitation
• wall turbulence
• gas–liquid two-phase flow
• phase change
• direct numerical simulation

Acknowledgements

This research was completed using the supercomputer at ACCMS, Kyoto University. The payment for using the supercomputer was provided by CII, University of Fukui.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Takashi Ohta http://orcid.org/0000-0002-9633-8975