Numerical Study on Effect of a Thermal Bump in Supersonic Flow Control

Abstract

ow stability characteristics are assessed by varying the initial disturbance amplitude, frequency and the spanwise width of the heating element. A high-resolution upwind-biased Roe method is used with the fourth-order accurate Runge-Kutta scheme together with a suitably rened mesh. The perturbed ow eld is analyzed in detail for Tw = 751 K, f = 100 kHz and w=1 mm. The thermal bump generates two pairs of counter-rotating streamwise vortices formed at the four edges of the element. When the heat source is pulsed, vortex shedding is observed. These vortices interact with each other, generating a complicated vortical eld. The vortices grow in the spanwise direction with the downstream distance. The simulations show that the vertical perturbation velocity decays faster than the other two components, and the streamwise perturbation velocity produces a low-speed region downstream of the centerline and two high-speed regions on either side. The disturbance energy shows that the streamwise kinetic disturbance energy dominates over other components. The study of the dierent initial disturbance amplitudes demonstrates the existence of non-linear effects while the frequency variation highlights the importance of pulsing in determining the features of the downstream disturbance. It is found that the eect of halving the spanwise width of the thermal disturbance is to modestly increase the disturbance energy.