Analysis of flow behaviour in a two sided lid driven cavity using lattice boltzmann technique

The flow characteristics of lid-driven cavity are simulated using the Lattice Boltzmann Method (LBM). For achieving the best numerical stability, this problem is solved using two-dimensional nine directional lattice model (D2Q9). Single Relaxation Time-BGK approximation is used for collision of particles. The effect of various Reynolds numbers (100, 1000, 2000 and 5000) and aspect ratios (1, 2 and 4) in the flow characteristics is studied. In this problem two cases of boundary conditions are considered, in the first case, the top and bottom walls move in the same direction towards right side with uniform velocity (u = 0.1) and in the second case, the walls move in opposite direction with same velocity. For validation, velocities and the locations of primary, secondary, ternary vortexes obtained from the simulation are compared with existing literatures and found to be in good agreement. The results show that at higher Reynolds number (Re), there is a formation of secondary and ternary vortexes. The shape and size of the vortexes changes with increase in aspect ratio (K). For lower Re, primary vortexes only were observed. However, at low Re with increase in K, there is a formation of secondary vortexes. The pressure contours are also presented.