Influence of an upstream attached flat plate on the newtonian flow past a square cylinder

Abstract

In this study, thelattice Boltzmann method is used to analyze the flow around a single square cylinder with a flat plate attached atfront side of the cylinder. In order to perceive the impact of the attached flat plate on flow characteristics of the square cylinder, the dimensionless plate lengths are variedfrom 0.1 to 6, while the Reynolds number is fixed at 150. Corresponding to all plate lengths the well-known von Karman vortex street is observed in the cylinder’s wake region. However, the increase in plate’s length results in reducing recirculation regions, enlarging the wake length and thus stabilizing the flow. The fluid forces and velocity field are significantly affected with increment in plate length. A maximum of 65%, 76%, 62% and 11% reduction is observed in the mean drag coefficient (CDm), root-mean-square values of drag coefficient (CDrms) and lift coefficient (CLrms) and amplitude of lift coefficient (CLAmp), respectively, as compared to single cylinder without a flat plate. Pressure is also found to be significantly reduced due to presence of plate at front surface of cylinder.