Fluid Flow and Local Heat Transfer around Two Cubes Arranged in Tandem on a Flat Plate Turbulent Boundary Layer

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Experimental studies were performed to investigate the fluid flow and local heat transfer around two cubes arranged in tandem on a flat plate turbulent boundary layer. The Reynolds number, based on the cube height d, ranged from 4.0×10³ to 3.2×10⁴. The thickness of the turbulent boundary layer δ was δ/d≤2.17. The surface temperature distribution around the cubes was measured with thermocouples under conditions of constant heat flux. The effect of spacing b between two cubes was clarified in the range of 0.33≤b/d≤1.33. In the case of b/d≥0.67, the horseshoe vortex is formed in front of each cube. However, at b/d=0.33, it does not form in front of the 2nd cube. The local heat transfer is high in the horseshoe vortex regions and the flow reattaching regions. The average Nusselt numbers of 1st cube, ¯Nu, and 2nd cube, ¯Nu, are expressed as ¯Nu=0.24Re^0.66 and ¯Nu=0.27Re^0.64, respectively. They are virtually unaffected by the spacing. However, that of base plate between two cubes, ¯Nu, has a maximum value of ¯Nu=0.47Re^0.60 at about b/d=0.67.