Scaling of Skin-Friction Reduction Based on Plasma-Generated Streamwise Vortices

This work aims to investigate experimentally the dependence on the friction Reynolds number Reτ of drag reduction (DR) in a turbulent boundary layer (TBL) using plasma-generated streamwise vortices (PGSV). The Reτ examined is from 520 to 750. The developed actuator array produces three pairs of streamwise counter-rotating vortices in a fully developed TBL. The measured maximum spatially averaged drag reduction DRmax reaches 70% over the FE area (210 mm × 240 mm) at Reτ = 520. It has been found for the first time from the empirical scaling analysis of obtained experimental data that the DR scales with the strength of PGSV. which may have a profound impact upon engineering applications.