Effects of interval blowing on drag reduction in compressible channel turbulent flows

Direct numerical simulations of channel turbulence using interval blowing control at two Mach numbers (0.8 and 1.5, respectively) were conducted. The main goal is to utilize turbulence statistics to examine the evolution of skin friction drag from the blown region to the non-blowing interval. The findings indicate that internal blowing control effectively reduces skin friction drag in both the blowing and non-blowing regions relative to the uncontrolled scenario. In the subsonic turbulent boundary layer, the skin friction drag first decreases monotonically before increasing as it traverses the final few strips. Nevertheless, the skin friction drag of supersonic airflow increases as it traverses the blowing strips and diminishes upon entering the non-blowing zone. This is intimately linked to the production and dissipation of turbulent kinetic energy. Furthermore, the average velocity profile, intensity of turbulent Reynolds stress, and the evolution of vortices can be significantly influenced by the implementation of interval blowing strips.