Viscous Flow on Surfaces with Streamline Riblets

摘要

The viscous sublayer of a turbulent boundary layer on a surface with riblets was calculated. Only the mean flow constituent was considered: using conformal mapping viscous flow on various riblet configurations was determined, including sawtooth profiles and U-shaped groove configurations. The decreased turbulent drag of riblet surfaces is caused by hampering the fluctuating cross flow. The efficiency of the riblets depends on their protrusion height. However, the protrusion height cannot be increased beyond 22 percent of the lateral rib spacing, which limits the drag reduction potential of riblet surfaces.