In the present study, the effects of a single rib on the local heat transfer around a bluff body are examined by using the steady state liquid crystal technique. By varying the spacing between the bluff body and the rib, the interaction between the rib and the bluff body can be controlled. The bluff body is oriented vertically towards the flow direction and spans the whole height of the channel. The bluff body has a rectangular cross-section (height b = 80 mm, width 40 mm) while the rib ! has a square cross-section (rib height e = 10 mm, rib width 10 mm). The rib is placed in the upstream region of the bluff body either by a spacing L = 100 and 50 mm to yield non-dimensional spacing to rib height ratios L/e = 10 and 5 respectively. Here, the re-attachment length (x_R) for a single rib is about 7.5e. The values of the Reynolds number based on the channel hydraulic diameter (D_h) are 55,000 and 89,000. The experimental results revealed that the presence of the rib at L/e = 10 has a more pronounced effect on the enhancement of the heat transfer upstream region of the bluff body. The effect of different L/e on the local Nu number distribution in the wake of the bluff body is small.
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