Enhancing Heat Transfer with Wavy Walls and Unsteady Flow Perturbations

Recent studies have used optimization to determine fluid flows that can efficiently cool heated objects. First we will present results on optimal fluid flows and wall shapes for heat transfer. We will then examine recently discovered steady optimal flows through a heated channel, and use a perturbation method to find nearby unsteady flows that convect more heat - up to 80% - for a given amount of power needed to move the flow. The unsteady perturbations consist of vortices, small or large, that move along the channel walls and disrupt the thermal boundary layer.