Prediction of separation flows around a 6:1 prolate spheroid using RANS/LES hybrid approaches

• 来源期刊: 力学学报（英文版）
• 年，卷（期）: 2007,（4）
• 页码范围: 369-382
• 页数: 14页
• 语种: 英文

摘要

This paper presents hybrid Reynolds-averaged Navier-Stokes (RANS) and large-eddy-simulation (LES) methods for the separated flows at high angles of attack around a 6:1 prolate spheroid. The RANS/LES hybrid meth-ods studied in this work include the detached eddy simula-tion (DES) based on Spalart-Allmaras (S-A), Menter's k-w shear-stress-transport (SST) and k-ω with weakly nonlinear eddy viscosity formulation (Wilcox-Durbin+, WD+) mod-els and the zonaI-RANS/LES methods based on the SST and WD+ models. The switch from RANS near the wall to LES in the core flow region is smooth through the implementation of a flow-dependent blending function for the zonal hybrid method. All the hybrid methods are designed to have a RANS mode for the attached flows and have a LES behavior for the separated flows. The main objective of this paper is to apply the hybrid methods for the high Reynolds number separated flows around prolate spheroid at high-incidences.A fourth-order central scheme with fourth-order artificial viscosity is applied for spatial differencing. The fully implicit lower-upper symmetric-Gauss-Seidel with pseudo time sub-iteration is taken as the temporal differentiation. Com-parisons with available measurements are carried out for pressure distribution, skin friction, and profiles of velocity,etc. Reasonable agreement with the experiments, accounting for the effect on grids and fundamental turbulence models,is obtained for the separation flows.