Numerical Analysis of a Two-Dimensional Jet Impinging on an Oscillated Heat Transfer Surface

Numerical analyses were performed to determine the oscillation effect of an impingement surface on the impingement heat transfer and flow with a confined wall. As a moving boundary problem, two-dimensional governing equations were solved for the Reynolds numbers Re=200 and 500, the Prandtl number Pr=0.71, the dimensionless space between the nozzle and impingement surface H=1.0, and the Strouhal number Sf=0-1.0. Oscillation induced both the enhancement and depression of the local heat transfer. The local heat transfer was improved at a comparatively low frequency due to the flow fluctuation. On the other hand, at a high frequency, it was depressed due to the flow in an upper direction near the impingement surface. The oscillation effect spatially appeared downstream after the impingement.