DOI: 10.5176/2251-1911_CMCGS18.15
Authors: Atendra Kumar, Rajendra K. Ray
Abstract:In this paper, a numerical simulation for vortex shedding control behind a square cylinder in shear flow is carried out in the presence of small control cylinders placed at the downstream locations of the main cylinder. The computations are carried out by using higher order compact (HOC) finite difference scheme for Reynolds number Re=100 and shear rate K=0.0,0.05,0.1. The gap distance between the main cylinder and control cylinder is fixed at d/2, where d is the side length of the main square cylinder. We investigate the effect of shear rate and the presence of small control cylinders on the vortex shedding phenomenon behind the main square cylinder. The results have been shown in terms of vorticity contours, lift coefficients and their corresponding power spectra, drag coefficients, phase diagrams and centerline velocity fluctuation for all the parameter values considered here. Three different types of situations are considered depending upon the locations of the control cylinders. In the first case, one single control cylinder is placed near the upper downstream corner of the main cylinder. In the second case, one single control cylinder is placed near the lower downstream corner of the main cylinder. Finally, we considered two control cylinders placed at the upper and lower downstream corners of the main cylinder. The vortex shedding frequencies are almost equal and decrease with increasing K values for first two cases. The complete suppression of the vortex shedding has been seen for the third case considered here.
Keywords: Unsteady shear flow, flow control, Vortex shedding, HOC scheme, Vorticity contours, lift drag coefficients.
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