Numerical investigation on compressible flow around a cylinder in proximity to the heated wall

In this study, direct numerical simulations were conducted to investigate the compressible flow around a circular cylinder near a heated wall at a Reynolds number (Re) of 500 and a Mach number (Ma) of 0.4. The heating ratio T* ranging from 1.0 to 1.6 represents the different situations of a heated wall, whereas the gap ratio ranges from 0.3 to 1.0. This study analyzed the impact of heating effect and wall proximity on flow characteristics and aerodynamic forces. The results indicated that the stability of the flow was enhanced as the gap ratio decreased or the heating ratio increased. Through the calculation of enstrophy, it was found that the strength of shedding vortices weakens with a decrease in gap ratio or an increase in heating ratio. Furthermore, the mean drag coefficient decreases as the heating ratio increases or the gap ratio decreases. In contrast, the mean lift coefficient initially decreases and then increases as the gap ratio decreases. Finally, the drag reduction mechanism was analyzed by examining the pressure distribution on the surface of the cylinder.