FORCED CONVECTION HEAT TRANSFER FROM ELLIPTIC CYLINDERS IN TANDEM ARRANGEMENT.

An experimental investigation has been carried out to clarify heat transfer characteristics and flow behaviors around four elliptic cylinders having an axis ratio 1:2. They were placed in tandem arrangement with a constant angle of attack to the upstream uniform flow. The testing fluid was air and the Reynolds number based on the major axis length, c, ranged from about 15000 to 70000. The angle of attack was varied from 0 degree to 90 degree at 30 degree intervals and the nondimensional cylinder spacing l/c from 1. 25 to 4. 0, where l denotes the streamwise distance between the neighbouring cylinder centers. It has been found that the heat transfer features vary drastically with the angle of attack and also with cylinder spacing, corresponding to the great change of the flow behavior. Further the heat transfer capability of the present elliptic cylinders is shown to be comparable to that of the in-line circular cylinders at narrower cylinder spacings and at smaller angles of attack.