Forced Separation Unsteadiness in a Sharp Fin Induced Shock-Wave / Boundary-Layer Interaction

Using detached eddy simulations, unsteady perturbations were injected into the incoming boundary layer of a Mach 2, sharp-fin induced shock-wave / boundary-layer interaction to explore flow control of the separation unsteadiness. Analysis of the baseline flow showed that the separation shock fluctuated at a lower frequency range and amplitude, compared with the unsteadiness of the separation position. From the baseline data, an artificial upstream time-periodic body force was designed using profiles of the streamwise velocity perturbations in the incoming boundary-layer, which were conditionally averaged based on the separation position. Simulations with forcing showed that both the frequency and spanwise form of the forcing had significant effects on the separation unsteadiness. The responses of the separation shock and separation position were generally dissimilar. These responses were strongest with a forcing frequency representative of the baseline separation shock unsteadiness, and with a particular spanwise form that accounted for the mean spanwise flow near separation. These results demonstrate that the separation unsteadiness of the sharp-fin flow can be modulated by upstream forcing of a certain form, and highlight potential flow control strategies for this flow.