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Abstract
The structure of the flow field and its effect on the heat transfer characteristics of a jet array system are investigated numerically in steady state for Reynolds numbers between 100 and 400. A section of the array consisting of 24 square jets (3 rows × 8 columns) impinging on a heated flat surface is considered as a representative pattern. The simulations have been carried out for jet-to-jet spacings in the range 2D–5D and for nozzle exit-to-plate distances between 0.25D and 2D, where D is the jet width. The results show that the streamwise profile of the Nusselt number exhibits strong periodic oscillations. For small nozzle-to-plate spacings (L z < D) and low Reynolds numbers, the amplitude of the periodic oscillations is attenuated as one proceeds in the downstream direction. For Re > 100 and L z ≥ D, secondary peaks are formed downstream as a result of deflection of the jets by the crossflow resulting from upstream jets. The superimposition of the secondary peaks distorts the periodic Nusselt number profile.