An extension of the Lattice Boltzmann Method for simulating turbulent flows around rotating geometries of arbitrary shape

Abstract

A Multi-Relaxation-Time Lattice-Boltzmann Method (MRT-LBM) is proposed for simulating unsteady three-dimensional turbulent flows. Turbulence modeling is performed with a state-of-the-art Large-Eddy-Simulation (LES) approach based on a explicit subgrid-scale model within the LBM framework. Additionally, a computational technique for treating rotating geometries is presented, which is based on an interpolation technique for the boundary fluid-cell interface. A two dimensional double shear layer and a three-dimensional Taylor-Green vortex will be testcases for the MRT scheme. Beyond this, the MRT scheme including the turbulence model will be validated with a two dimensional flow around a square cylinder at low and high Reynolds numbers. Results of the vorticity field and the global Strouhal number of the detaching flow will be shown for the square cylinder. The laminar flow around a rotating cylinder is simulated with an interpolation based technique and results of the drag and lift coefficient will be shown and compared to reference cases. Finally, the three-dimensional flow at high Reynolds numbers around a rotating cylinder will be presented, which includes both techniques for turbulence modeling and complex boundary treatment.