Viscous Drag Reduction with Surface-Embedded Grooves.

Turbulent drag reduction in wall-bounded flows is investigated experimentally by considering the dynamic effects provoked by large variation of anisotropy in the velocity fluctuations. Deductions based on the analysis of near-wall turbulence lead to the design of the grooved surface topology, for which it is demonstrated experimentally that it can produce a maximum drag reduction of DR ≃ 25%. The drag reduction effect persisted in a narrow range of flow velocities and for the reported experimental conditions corresponds to groove dimensions of about 0.8 viscous length-scale. [ABSTRACT FROM AUTHOR]