Investigation of the Flow Physics in an Oscillating Lid-Driven Cavity with a Concentric Square Obstacle Using the Lattice Boltzmann Method

In the present study, the flow physics within an oscillating lid-driven cavity in the presence of a concentric square obstacle is simulated using the in-house developed Lattice Boltzmann Method (LBM) code. The effects of Reynolds number (Re), oscillating frequency of the moving top lid (ω), and size of the square obstacle (Ls*) on the fluid mixing in the enclosed cavity space are discussed. It is noticed that the number of vortices and flow recirculation and mixing inside the cavity rises with an increase of Re and Ls*. However, an increase of ω significantly suppresses the unsteadiness in the cavity region and thereby reduces the fluid mixing.