Traveling Wave: A Concept for Enhancing Underwater Vehicle Performance

摘要

Over the past 25 years, Soviet researchers have been investigating the potentialof a traveling wave, imposed at the surface of a body, to reduce the drag of the body. The Soviets contend that when properly posed, the traveling wave will produce a system of entrained vortices which lead to a significant reduction in shear stress without a concomitant penalty in pressure drag. The possibility of using vortical flow to reduce drag has been known in the United States for a number of years. Suitably positioned transverse slots can result in entrained vortices and a significant reduction in base drag over the closure of a bluff body. In addition, experiments at NASA Langley have shown that ordered periodic vorticity injected into a turbulent boundary layer near the wall results in 20 to 25 percent drag reduction over nominal flat plate values. While the Soviet literature presents some theory and some experimental results, it is often incomplete and difficult to follow. The parameter space for successful implementation of the traveling wave has been, until now, elusive. Identification of the appropriate parameter space requires an understanding of the physics of the traveling wave. The purpose of the research reported has been to develop an understanding of the traveling wave phenomenon through analytical and computational investigations. This report presents the results of research to date and maps out a plan for determining the feasibility of implementing the traveling wave for drag reduction on underwater vehicles. Drag reduction; Submarines; Vortices; Foreign Technology.