High-frequency actuator control of air flow near a circular cylinder: Impact of the discharge parameters on the cylinder aerodynamic drag

The impact of capacitive high-frequency surface discharge on a flow around a circular cylinder is studied at airflow velocity of $20$–$100$ m/s and the Reynolds numbers $\mathrm{Re}<2.4\times10^5$. The power of the discharge was modulated at a frequency of $10^2$–$10^4$ Hz, corresponding to the Strouhal number $\mathrm{St}=0.1$–$10$. It is shown that the distribution of pressure in the wake behind the cylinder is significantly influenced by the discharge. A decrease in the average diameter of the wake is observed. The parameters of the discharge were measured: the gas temperature, heating rate in the discharge region, and velocity of discharge propagation.