Flat Plate Reduction In A Water Tunnel Using Riblets

Streamwise microgroove surface modifications, known as riblets, are known to alter the structure of the turbulent boundary layer such that the skin friction drag over the surface is reduced. For this investigation, velocity profile measurements were used to calculate the drag on a flat plate, both with and without riblets, in a high-speed water tunnel. The vinyl riblet surface produced a maximum drag reduction of 8.1% + or - 2.5% at a nondimensional groove spacing, + or - of 13.1. If the results obtained in the laboratory can be realized for torpedoes and other submersibles, significant improvements in vehicle speed or fuel economy will be achieved.