Abstract:

Drag is generated by the interaction and contact of a solid body with a fluid. Drag implies a great role on fluid mechanics and aerodynamics while it is conducted for any kind of moving object of different shape. A significant number of experiments were executed for reduction of drag force because drag causes high power consumption and also structural failure of the object. Reduction of drag force of circular cylinder by attaching circular rings is described in this experiment. For accomplishing this experiment models are tested in 36x36x100 cm subsonic wind tunnel. Drag measurements are carried out by using an external balance. Drag force over circular cylinders of different diameter without any rings are tested first. Then circular rings attached circular cylinders are tested. It is observed that there is reduction of drag even though the projected area increased because rings causes more attached flow than the plain cylinder. The optimum value of drag reduction is found when ring is 1.3d and aspect ratio of cylinder is approximately 12. The experimental results show drag reduced by this optimum configuration is 25%

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