Control of vortex shedding around a square cylinder using the moving wall method

Karman vortices are generated in the wake of square cylinder placed in a uniform flow, producing unsteady lift forces that can cause structural vibrations and damage. This study investigates a flow control method using moving wall actuation on the downstream face of a square cylinder to suppress Karman vortices. Numerical simulations based on the incompressible Navier–Stokes equations were performed under a Reynolds number of 100, varying the wall velocity (vpa = 0.1 to 5.0).The results showed that as the wall velocity increased, the Karman vortices gradually weakened and eventually disappeared. At vpa = 0.9, where the vortices were not fully suppressed but their shedding location shifted downstream, the RMS values of lift and drag decreased by 96.1% and 17.2%, respectively. At vpa = 3.2, where vortex shedding was completely suppressed, these values were further reduced to 99.9% and 82.4%. Flow visualization confirmed that with increasing control intensity, the vortex shedding location moved downstream and ultimately vanished.