Numerical simulation for shear effect on vortex shedding behind a square cylinder

This paper is concerned with the numerical simulation of the flow-structure around a square cylinder in a uniform shear flow. The calculations were conducted by solving the unsteady 2D Navier-Stokes equations with a finite difference method. The effect of the shear parameter K of the approaching flow on the vortex-shedding Strouhal number and force coefficients acting on a square cylinder is investigated in the range of K = 0.0 to 0.25 through various Reynolds numbers from 500 to 1500. Computational results are compared with some existing experimental data and previous studies. The effect of shear rate on the Strouhal number and the force acting on the cylinder has a tendency to reduce the oscillation. The Strouhal number, mean drag and amplitudes of the fluctuating force tend to decrease as the shear rate increases but no significant change in the small shear rate. Increase the Reynolds number decreases the Strouhal number and increases the force acting on the cylinder. At high shear rate, shedding frequencies of the fluctuating drag and lift coefficients are identical.