Effect of Thermal Buoyancy on Vortex-Shedding and Aerodynamic Characteristics for Fluid Flow Past an Inclined Square Cylinder

Abstract

The present work aims to numerically investigate the upward flow of air past an inclined square cylinder with an incidence angle equal to 45o in the mixed convection regime at a fixed Reynolds number Re = 100. The governing equations are modelled by considering Boussinesq approximation. The critical Richardson number (Ric) for the suppression of vortex shedding (VS) is determined. By observing the instantaneous streamline patterns and the coefficient of lift plot with time near the critical value, it is found that VS suppression occurs at Ric = 0.78. Also, the aerodynamic characteristics such as lift and drag coefficient, the heat transfer characteristic, and the Strouhal number are studied by varying Ri in the range of [0.2, 1]. The role of thermal buoyancy on the aerodynamic parameters such as drag and lift coefficients, Nusselt number and Strouhal number are also studied in the mixed convection regime. It is found that mean drag coefficient and Nusselt number increases with the increase in Ri, and no lift is developed for any Ri, while the Strouhal number increases with increase in Ri and vanishes at a critical Richardson number. Further, the effect of thermal buoyancy on streamlines, isotherms and iso-vorticity contours are also presented.