| The dissertation demonstrates the potential for shockwave-turbulent boundary layer interaction control in air using low current DC constricted surface discharges forced by moderate strength magnetic fields. Experiments are conducted in a Mach 2.6 indraft air tunnel with discharge currents up to 300 mA and magnetic field strengths up to 5 Tesla. Separation and non-separation inducing shocks are generated with diamond shape shockwave generators located on the wall opposite to the surface electrodes, and flow properties are measured with schlieren imaging, static wall pressure probes and acetone flow visualization. Also, an efficient, time dependent, two-dimensional Navier-Stokes numerical code for shockwave boundary layer interaction in air is developed. To replicate the experiments done at high Reynolds number, the code is divided into time independent and time dependent regimes to significantly reduce computation time. The effect of plasma control on boundary layer separation depends on the direction of the Lorentz force ( j&d16;xB&d16; ). It is observed that by using a Lorentz force that pushes the discharge upstream, separation can be induced or further strengthened even with discharge currents as low as 30 mA in a 3 Tesla magnetic field. If shock induced separation is present, it is observed that by using a Lorentz force that pushes the discharge downstream, separation can be suppressed, but this required higher currents, greater than 80 mA. Acetone planar laser scattering is used to image the flow structure in the test section and the reduction in the size of recirculation bubble and its elimination are observed experimentally as a function of actuation current and magnetic field strength. Computational results are in good agreement with experiments in terms of the flow structure as shown by Schlieren imaging, acetone planar laser scattering, and the static pressure profile on the test section wall. |
