Influence of subgrid-scale models on cavitation phenomenon around a 3D twisted hydrofoil

Abstract

ObjectiveThis paper aims to explore the suitability of mesh density and subgrid-scale model for the numerical simulation of three-dimensional twisted hydrofoil. MethodsThe large eddy simulation (LES) method and Schnerr-Sauer (S-S) cavitation model are used to simulate the unsteady cavitation flow of a Delft Twist11N three-dimensional twisted hydrofoil. Three sets of grid with different density and three types of different subgrid-scale models are mainly studied to identify the effects on the Twist11N hydrofoil cavitation evolution process, cavitation shedding frequency and time-averaged lift and drag coefficients.ResultsThe results show that appropriate grid refinement can not only capture more unsteady cavitation evolution phenomena such as the shedding of smaller cavities and the inception and collapse of horse-shoe-shaped cloud cavities, but also obtain more exact cavity shedding frequency, time-averaged lift and drag coefficients, and time-averaged pressure distribution. Among the three subgrid-scale models, compared to the algebraic wall-modeled LES model (WMLES) and Smagorinsky-Lilly (SL) model, the wall-adapting local eddy-viscosity (WALE) model better captures the evolution of sheet and cloud cavitation, and has better accuracy in predicting the frequency of cavity shedding,time-averaged lift, drag and pressure coefficients.ConclusionIt is recommended to adopt the LES method with the WALE subgrid-scale model for the numerical simulation of unsteady cloud cavitation.

Keywords

• three-dimensional twisted hydrofoil
• cloud cavity
• large eddy simulation
• subgrid-scale model
• grid density