Heat Transfer Enhancement and Drag Reduction of Flat Plate Normal to Airstream : Flow Control Using a Rod

To control the flow around a flat plate, a small rod was set upstream of the plate. The chord length of the plate, D, was 50mm and the diameter of the rod, d, and the distance between the axes of the rod and plate, L, were varied. The Reynolds number ranged from l.3×104 to 7.7×104. For the case without vortex shedding from the rod, the shear layer from the rod reattaches on the front face of the plate. Consequently, quasi-stationary vortices are formed between the rod and the plate. In this case, at d/D=0.4 and L/D=1.4∼2.0, the maximum reduction of total drag coefficient is 20∼30%, the average heat transfer on each face increases and the overall heat transfer increases by about 40∼50% compared with values obtained without the rod in place.