Numerical Simulation of High Reynolds Number Wall Bounded Flow

Licentiatavhandling, 2005

In this thesis, four different numerical methods are used for predictions of high Reynolds number (Re), wall bounded flows; Large Eddy Simulation (LES) with two different subgrid (turbulence) models, the One Equation Eddy Viscosity model (OEEVM) and the Mixed Model (MM), Monotone Integrated LES (MILES), Detached Eddy Simulation (DES) and Reynolds Averaged Navier Stokes (RANS). The LES calculations are combined with a wall model based on the law-of-the-wall and in DES a hybrid RANS/LES method is used for handling the near wall region. These methods are validated against several well known, generic flow cases; a jet flow at Re=95,000, fully developed turbulent channel flow at Ret=395, 595 and 1800, flow past a circular cylinder at Re=3900 and 140,000, flow past a prolate spheroid at 10° and 20° angle of attack at Re=1.6·10^6, flow around an axisymmetric hill at Re=1.3·10^5 and flow past the DARPA Suboff configuration AFF-1 and AFF-8 at Re=12·10^6. The focus of this thesis is on LES and subgrid modeling in LES, and LES-MM and LESOEEVM is used in all validation cases, while DES is used in the axisymmetric hill and the circular cylinder cases. The MILES model is only used in the cylinder case and RANS only in the axisymmetric hill case. A careful theoretical investigation is performed of LES-MM, where a reformulation of the LES equations is proposed. LES-MM also performs the best prediction of the flow field compared with the other numerical methods, especially for the more complex cases. Keywords: LES, DES, subgrid model, validation, near-wall, numerical simulation, high Reynolds number, turbulence