Heat and mass transfer of rectangular waveform inflow impinging synthetic jet at same strouhal number

Heat removal capacity of slot synthetic jet impinging on target plate with constant heat flux is numerically studied in this work. The signal of synthetic jet velocity is rectangular waveform; parameters investigated cover dimensionless jet-to-surface distance H/w=2 and 4, Reynolds number Re 10,000 - 20,000, oscillating frequency f 10 Hz - 20 Hz, and corresponding Strouhal number St of 0.1598. The results indicated that heat transfer rate of synthetic jet at H/w=4 is higher than that at H/w=2 with other conditions unchanged, which is attributed to the discrepancy between flow structures. The extent of Nusselt number Nu enhancement as a result of Re promotion, increases with H/w. Moreover, under the circumstance of rectangular waveform and identical H/w, the similarity of area-averaged Nusselt number <Nu> variation process emerges under the same St that roots in the comparability of flow field evolution.