Scrutinizing lattice Boltzmann methods for direct numerical simulations of turbulent channel flows

摘要

The paper reports on the predictive performance of Lattice Boltzmann methods in turbulent channel flows. Attention is confined to model-free (direct) numerical simulations at Re-tau = 180 using essentially different collision models, i.e. the Bhatnagar-Gross-Krook (BGK), the Multiple-Relaxation-Time (MRT) and the Cumulant model. The three approaches are assessed by a comparison of the predicted mean flow and turbulence statistics against benchmark Navier-Stokes solutions. Initial studies employ a fine isotropic grid which resolves all relevant scales. Subsequently, a sequence of four gradually decreasing resolutions is utilized to analyze the sensitivity of the collision models for an inadequate resolution. Moreover, the influence of the Mach number and the discretization on the predictive accuracy of the weakly compressible LBM framework is briefly addressed.