The heat-transfer characteristics in the unsteady laminar fluid flow around a pair of diamond-shaped cylinders in staggered arrangement are investigated by means of numerical simulation, in which some results are compared with that by flow visualization method. Emphasis is placed on the effects of the Reynolds number, Re, and the ratio of cylinder separation distance to length of diamond-shaped cylinder, s/d, on the flow and thermal fields. It is found that (i) the generation of von Karman vortex streets occurs behind the diamond-shaped cylinders, (ii) each vortex generated from each cylinder is interacted whose characteristics are affected by s/d, (iii) the thermal diffusion is also caused behind each diamond cylinder whose nature is characterized by s/d, and occurs only in the vicinity of the diamond cylinders, (iv) this trend becomes clearer with an increase in the Reynolds number.

thermal fluid flow, numerical simulation, flow visualization, thermography, twin diamond-shaped cylinders, staggered arrangement.