A source of controlled nonstationary harmonic flow disturbances

The flow in the vicinity of the source of controlled harmonic non-stationary perturbations of a gas medium, applicable for generating Görtler vortices in a compressible boundary layer, is studied. The source has a flat surface with linearly arranged cylindrical channels, leading alternately to two cavities of variable volume. Various configurations of the source are considered: with separate channel outlet openings and with a slit opening above them. Numerical simulation is performed in the Solid Works Flow Simulation package, and experimental measurement of gas velocity is realized by the PIV method. The developed source is shown to create periodic velocity fluctuations with an amplitude of up to 2 m/s at a frequency of 1 kHz near the surface. The shapes of the profiles of velocity normal to the surface along the source are close to sinusoidal in both time and space.