MECHANISM OF HEAT-TRANSFER ENHANCEMENT DUE TO SELF-SUSTAINED OSCILLATION FOR AN IN-LINE FIN ARRAY

Numerical analysis of the instantaneous flow and thermal fields was ca rried out for an in-line type of fin array for the second laminar flow regime characterized by self-sustained flow oscillation. Flow instabi lity occurring in the wake of a fin leads to the production of the scr ibes of counter-rotating vortices. They accelerate recovery of the wak e and are thus effective in enhancing the heat transfer of the downstr eam fin. Such vortices hit the leading edge of the downstream fin one after another and induce two particular types of elementary fluid moti ons near the fin surface, which are effective again in the enhancement of the fin heat transfer. Such fluid motions are also found to produc e the dissimilarity between the momentum transfer and heat transfer.