Drag of the Insect-inspired Axisymmetric Body with the Small Length-to Diameter Ratio*

Limited data are available on aerodynamics of finite axisymmetric bodies with a small length-to-diameter ratio when a body is in the face-forward position with respect to the flow direction. Such bodies and their orientation are of particular interest for the concept of urban mobility, for example. An insect-inspired body was created for the study to investigate whether drag reduction would be achieved to compare with a double bullet and an ellipsoid based on the V-22 Osprey assembly adopted from NASA publications. The cicada body was used as a prototype based on our previous works. The drag measurements were conducted in the water tunnel at the Department of Mechanical Engineering, University of New Mexico. The incoming flow in the experiments was laminarized, and the bodies were axially oriented with the flow direction at a zero-degree angle of attack. It was found that the bio-inspired design outperformed all others over most of the range of considered Reynolds numbers based on the diameter of the design maximum cross-section up to 36,400.