CFD analysis of the effects of flow and thermal oscillations in heat transfer of impinging jet

A horizontal laminar buoyant impinging slot jet on an isothermal vertical plate was analyzed using ASNYS-Fluent simulation software. The study mainly focused on oscillations of velocity and temperature occurring in the laminar regime of a jet shear layer to investigate the effect of oscillations in heat transfer. The SIMPLE technique with finite volume method is used based on a semi-staggered mesh created. The predicted simulation results of heat transfer data and Strouhal number for isothermal jet flow against Reynolds number on jet impingement are validated with literature results. The predicted numerical study results are in good agreement with the experimental results. Subsequently, the parametric study is carried out to investigate the periodic oscillations that occur in the jet structure (shear layer). The results show that the standoff distance (H) and Reynolds number play a vital role in the critical transition of periodic to nonperiodic oscillations. Also, the nature of jet oscillations is more significant based on buoyancy in the jet flow and it is observed that in the mixed convective regime, an earlier transition from periodic to nonperiodic occurs as the oscillation frequency reduces which affected impingement heat transfer in low-speed jets. Small standoff distances (H < 10) resulted in better heat transfer.