Suppression of Instability Waves in a Stochastically Excited Turbulent Low-Speed Jet Using Feedforward Control

For the first time, the possibility of feedforward control of coherent structures (instability waves) in a low-speed stochastically excited turbulent jet at Mach M = 0.11 and Reynolds numbers and Re = 1.2 × 10⁵, respectively, was demonstrated. Control perturbations were introduced into the jet using a plasma actuator based on a barrier discharge, placed on the edge of the nozzle. The jet was excited by natural broadband perturbations. The control signal was obtained with a hot-wire anemometer installed inside the nozzle. A 2-dB reduction in velocity fluctuations associated with instability waves was obtained along the entire length of the jet in the Strouhal number range 0.2 ≤ Sh ≤ 2. It is shown that suppression of perturbations leads to some reduction in the thickness of the shear layer at the jet boundary.