Effects of thermal induced buoyancy forces on the vortex shedding of a circular cylinder

Thermal effects on the vortex shedding of a circular cylinder are studied numerically under laminar flow conditions for flows along (parallel but in a direction opposite) and perpendicular to the direction of gravity. When the flow is parallel to the direction of gravity, the process of natural convection due to heating the cylinder helps reduce the vortex shedding. However, when the flow is set perpendicular to the direction of gravity, vortex shedding cannot be suppressed only by heating the surface of the cylinder. To analyze the suppression mechanism in this case, the cylinder is divided into four equal quadrants and each quadrant is heated to observe the effect on shedding behavior and the force coefficients. Results show that by merely heating the cylindrical quadrants, vortex shedding decreases but cannot be completely eliminated. However, simultaneous heating and cooling of different cylindrical quadrants can result in complete suppression of vortex shedding accompanied by drag inversion.