Viscous Flow Drag Reduction

Efficient operation of aircraft or hydrodynamic vehicles requires that the drag forces generated during their motion be as small as possible. Practical means of achieving significant drag reductions have long occupied vehicle designers, for such reductions translate directly into increased range, speed, and maneuverability, or to decreased fuel consumption. Of the various types of drag forces which arise, viscous, or skin friction, drag is one of the most important. For example, it can comprise up to 50% of the total drag on an aircraft in the cruise condition. Reduction of viscous drag has therefore been the object of many recent studies. In this volume, current work on drag reduction in viscous flows is presented and related progress is assessed. The papers are not reviews of particular areas of drag reduction per se, but represent summary reports of current research in promising approaches, of continuing fundamental studies of turbulent flows, and of attempts towards practical implementation of laboratory proven ideas. They were presented at the Symposium on Viscous Drag Reduction held in Dallas, Texas, on November 5-6, 1979. The papers are grouped into six specific areas, although there is some overlap among areas for several of the papers. The topics covered are laminar boundary layers, turbulent flows, nonplanar geometries, blowing and suction, polymer additives, and compliant surfaces. A brief overview of each area is provided by a recognized authority to highlight both relevant prior work and the importance of the paper to the drag reduction field.