Flow dynamics over a heated cylinder subjected to high temperature ratios

Abstract

Unheated, and heated flows with forced convection over a fixed circular cylinder are studied numerically. Reynolds numbers of 80, 100, 150, and 200 are considered at different temperature ratios (T∗) of 1.66, 2.33, and 3. Different thermophysical property models of the fluid were used and implemented. The aerodynamic forces occurring on the cylinder as vortex shedding took place were explored. The drag coefficient, lift coefficient, and Strouhal number are presented and discussed. Moreover, the surface heat transfer coefficient is analyzed for the different cases of heating. It was found that increasing the temperature ratio of the cylinder caused an increase in the static load and a decrease in the dynamic load on the cylinder. In addition, the effects of cylinder surface temperature on the vorticity contours are shown for different Reynolds numbers. It was observed that increasing the temperature ratio of the cylinder caused the vortices in the wake to stretch and become weaker. This leads to total suppression of vortex shedding if sufficient heating is provided. Moreover, while the surface heat transfer coefficient of the cylinder was observed to increase with the increase of Reynolds number at constant temperature ratio, increasing the temperature ratio of the cylinder at a constant Reynolds number reduces the heat transfer coefficient and suppresses the variation in between the upper and lower sides of the cylinder.