Simulation of Lid Driven Cavity Flow at Different Aspect Ratios Using Single Relaxation Time Lattice Boltzmann Method

In this paper, the single relaxation time (SRT) lattice Boltzmann equation was used to simulate lid driven cavity flow at different Reynolds numbers (100-5000) and three aspect ratios, K=1, 1.5 and 4. Due to restrictions on the choice of relaxation time in the single relaxation time (SRT) models, simulation of flows is generally limited base on this method and imposing a proper boundary condition will improve the capability and stability of this method. In this work, bounce back rule is imposed to consider no-slip boundary condition on solid walls and constant inlet velocity proposed by Hou was applied at the inlet side of the cavity. For a square cavity, results show that with increasing the Reynolds number, bottom corner vortices will grow but they won’t merge together. Also the merger of the bottom corner vortices into a primary vortex and creation of other secondary vortices was shown in the cases which the aspect ratios are bigger than one. Also at the case which the aspect ratio equals four, and Reynolds number reaches over 1000, simulations predicted four primary vortices, which were not predicted by previous SRT models. The results were confirmed by previous MRT model.

Cavity flow, Lattice Boltzmann, Aspect ratio, Vortex inegeration