Simulations of Two-Dimensional Multi-Stream Supersonic Jet Flow with Steady-Blowing Control

The present work performs a numerical investigation of a two-dimensional multi-stream supersonic jet flow with steady-blowing control. The nozzle flow of interest contains a main supersonic core flow at M = 1.6 and a bypass flow at M = 1.0, separated by a thick splitter plate, and an aft-deck is implemented to represent the structure of an aircraft. The mixing of the two flows forms a shear layer which breaks down to form vortical structures convecting downstream along the aft-deck. The shedding vortices produce tones that persist through out the flow field and generate intense surface pressure fluctuations. A relatively strong shock emanating from the proximity of the splitter plate trailing edge induces a region of flow separation along the nozzle wall. As a form of active flow control, a steady-blowing actuator, with injection at different angles, is introduced along the surfaces of the splitter plate. This control strategy aims to diminish the dominant shedding frequency, eliminate flow separation by weakening the shock strength, and reduce the high surface loading along the aft-deck. It is found that there is an an optimal actuation angle at each location that reduces the strength of the primary shock and mitigates flow separation. When actuation is introduced at the splitter plate trailing edge surface, the surface loading along the aft-deck is reduced for all actuation angles considered. Spectral analysis additionally confirms the dominant tone is reduced. Spectral proper orthogonal decomposition is applied to understand changes in the energy distribution when control is introduced. These results demonstrate the efficacy of steady-blowing control, prompting future investigation into unsteady control strategies to achieve the same control outcomes.