How vortices enhance heat transfer from an oscillating plate

TL;DR

This study investigates how vortex shedding from an oscillating flat plate enhances heat transfer, analyzing the effects of oscillation parameters and plate orientation at Reynolds number 100.

Contribution

It provides new insights into heat transfer enhancement mechanisms for flat plates, focusing on vortex dynamics and oscillation effects, which were less explored compared to cylindrical geometries.

Findings

Oscillation velocity and direction significantly influence heat transfer.

Large, strong vortices are shed depending on plate orientation.

Optimal oscillation parameters can maximize heat transfer efficiency.

Abstract

Oscillations of a heated solid surface in an oncoming fluid flow can increase heat transfer from the solid to the fluid. Previous studies have investigated the resulting heat transfer enhancement for the case of a circular cylinder undergoing translational or rotational motions. Another common geometry, the flat plate, has not been studied as thoroughly. The flat plate sheds larger and stronger vortices that are sensitive to the plate's direction of oscillation. To study the effect of these vortices on heat transfer enhancement, we compute the heat transfer from a flat plate with different orientations and oscillation directions in an oncoming flow with Reynolds number 100. We consider plates with fixed temperature and fixed heat flux, and find large heat transfer enhancement in both cases. We investigate the effects of the plate orientation angle and the plate oscillation direction, velocity, amplitude, and frequency, and find that the plate oscillation velocity and direction have the strongest effects on global heat transfer. The other parameters mainly affect the local heat transfer distributions through shed vorticity distributions. We also discuss the input power needed for the oscillating plate system and the resulting Pareto optimal cases.