Abstract
The drag reduction of cylinder having square dimpled surface was studied by measuring the drag force acting on the cylinder. Level of drag reduction was changed by an arrangement shape of the square dimples and Reynolds number. Drag of the cylinder was reduced about 28% with proper arrangement of square dimples. The flow field around the cylinder having dimples at the minimum drag was visualized by using post color ink in order to see the influence of the dimples. In this case, the separation points were shifted rearward and the wake region was smaller than that of the smooth surface cylinder.
