Heat transfer and flow around cylinder: Effect of corner radius and Reynolds number

This numerical study aims to investigate the flow around, heat transfer from, and aerodynamic forces on a square cylinder with the corner radius ratio r/R = 0.0 – 1.0 and Reynolds number Re = 40 180, where r is the cylinder corner radius and R is the half side width of the cylinder. The critical Reynolds number (Re_cr) for the onset of vortex shedding is found to vary from 49.5 to 46.75 when r/R is increased from 0.0 to 1.0. The dependence of the flow topology on the Re – r/R domain leads to four major flow patterns: steady trailing-edge separated flow, unsteady trailing-edge separated flow, unsteady separation-bubble flow, and unsteady leading-edge separated flow which are distinguished by flow separation, reattachment, boundary layer, and separation bubble. Accordingly, forces, Strouhal number, Nusselt number, and wake structure parameters all are dependent on r/R and Re. The dependence of each parameter is presented in the r/R – Re domain. The Strouhal number and Nusselt number are equally sensitive to both r/R and Re, increasing with increasing r/R and Re. Forces, on the other hand, are more sensitive to Re than r/R. The maximum velocity in the shear layer increases with r/R and Re while the boundary-layer displacement thickness behaves oppositely, shrinking with increasing r/R and Re.