Special Shaped Low Drag Bodies of Revolution Without Boundary-Layer Separation and Stagnation Points on the Noses

Abstract

High Reynolds numbers allow solving many important inverse problems of high-speed hydromechanics with the use of the ideal fluid approach. The shapes of elongated axisymmetric cavities and bodies of revolution with the prescribed pressure distribution were calculated with the use of asymptotical series for flow potential and exact solutions of Euler equations. In particular, axisymmetric and 2D shapes with negative pressure gradients on their surfaces were proposed in order to avoid separation of the boundary layer and reduce the drag. Wind tunnel experiments have confirmed the absence of separation on some bodies of revolution similar to the trunks of aquatic animals. The proposed shapes with sharp concave noses (similar to the rostrum of the fastest fish) have no stagnation points, pressure and temperature peaks. These special shaped bodies moving near the water surface cause much lower vertical velocities on its surface and can have a low wave resistance. These facts open prospects of using corresponding hulls for underwater and floating vehicles. In supersonic flows, they can reduce overheating of the noses.