Study of unsteady cavitation on NACA66 hydrofoil using dynamic cubic nonlinear subgrid-scale model

Xianbei Huang,Yaojun Li,Wei Yang,Zhuqing Liu

doi:10.1177/1687814015618166

Xianbei Huang, Yaojun Li + Show 2 more

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https://doi.org/10.1177/1687814015618166

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Abstract

In this article, we describe the use of a new dynamic cubic nonlinear model, a new nonlinear subgrid-scale model, for simulating the cavitating flow around an NACA66 series hydrofoil. For comparison, the dynamic Smagorinsky model is also used. It is found that the dynamic cubic nonlinear model can capture the turbulence spectrum, while the dynamic Smagorinsky model fails. Both models reproduce the cavity growth/destabilization cycle, but the results of the dynamic cubic nonlinear model are much smoother. The re-entrant jet is clearly captured by the models, and it is shown that the re-entrant jet cuts the cavity into two parts. In general, the dynamic cubic nonlinear model provides improvement over the dynamic Smagorinsky model for the calculation of cavitating flow.

Highlights

Cavitation is an unsteady flow phenomenon that usually has a negative or even destructive effect on hydraulic machinery embodied in pressure pulsation, erosion, and noise.[1,2] Cavitation occurs when the liquid pressure is lower than the saturated vapor pressure
According to the experimental results reported by Leroux et al.,[6] when the cavitation number defined as s ==(0:5rU‘2) reaches 1.25, the unsteady cavitating phenomenon will occur with the cavity periodically growing, shedding, and disappearing
We present the use of a linear model dynamic Smagorinsky model (DSM) and the new nonlinear model dynamic cubic nonlinear model (DCNM) for the calculation of cavitating flow around an NACA66 series hydrofoil and the simulation results are compared with the experimental data

Summary

Introduction

Cavitation is an unsteady flow phenomenon that usually has a negative or even destructive effect on hydraulic machinery embodied in pressure pulsation, erosion, and noise.[1,2] Cavitation occurs when the liquid pressure is lower than the saturated vapor pressure. In order to simulate the unsteady characteristics of cavitation through numerical calculation, it is usually assumed that the vapor and liquid are mixed and that they share the same velocity and pressure with a no-slip velocity condition between the two phases, as proposed by Kubota et al.[7] Based on this assumption, TransportBased Equation Modeling (TEM) is widely used in cavitating flows. With this method, an additional advection equation is solved.

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Results and discussions

Declaration of conflicting interests

Conclusion