Effect of vibrational mode excitation of N₂ in plasma actuators on shockwave induced boundary layer separation control

In this study analysis of the effect of energy deposition and subsequent release from the vibrational modes of N₂ is done using an efficient numerical code for shockwave boundary layer interaction (SWBLI) that was developed earlier.¹ Non-thermal surface plasma actuation using Lorentz force is evaluated further for effective shockwave induced boundary layer separation control within supersonic inlets using this modified numerical scheme. A significant part of the electrical power from the power supply is deposited in the vibrational modes of N₂,⁵ which may be released as heat over many molecular collisions. A time dependent computational 2D Navier-Stokes solver including the equation of state and parametric vibrational relaxation of N₂ for shockwave boundary layer interaction is developed. To replicate the experiments done at large boundary layer thickness, the code is divided in time independent and time dependent regimes to significantly reduce computation time. Further, time and space dependent force and volumetric heating are included to account for effects of plasma actuation. Computational results show that vibrational mode excitation and subsequent energy release due to vibration-translation (VT) relaxation have a very low impact on the performance of plasma actuation due to high relaxation times, low residence time of excited species in the test section and small size of recirculation bubble at high actuation currents.