THE EFFECT OF PULSATING AND STREAMWISE FLOW ON THE HEAT TRANSFER OF AN OBSTACLE

摘要

Pulsating flow has been found to generate extremely high turbulent kinetic energies at matched Reynolds numbers to streamwise flow and at low blockage ratios, and pulsating flow was found to augment the heat transfer by nearly 100% over streamwise flow. It was also observed that pulsating flow was more effective at cooling a flat surface than a protruding obstacle. Enhanced turbulent kinetic energy has been found to be more dependent on the strength of the pulsating flow than the magnitude of the streamwise flow, and it has been established that both frequency and amplitude play major roles in promoting enhanced mixing. Pulsating frequencies within the flow field were found to be conserved, and the generation of sub-harmonic and harmonic signals of the fundamental pulsating frequency were observed. It was also revealed that ultra-high pockets of energy at the fundament pulsating frequency were present but occurred at random periods.