Evolution of Flow Control Techniques on Supersonic Multi-Stream Jet Flow

Flow control is performed on a Multi-Aperture Rectangular Single Expansion Ramp Nozzle (MARS) using an array of microjets perpendicular to the flow. This campaign focuses on how the microjet’s configuration, location, and characteristics influence the highly complex flow problem presented by a multi-stream rectangular jet nozzle. The jet nozzle mixes two main flows: a core flow at Mach 1.6, and a bypass flow at Mach 1. This effectively simulates a modern multi-stream jet nozzle. The campaign is the culmination of two prior campaigns, passive control built into the splitter plate separating the two main flows of the nozzle, and active control via a microjet array just downstream from the splitter plate. The goal of this campaign being to replicate, with active control, the passive control’s successes as effective mixing and noise mitigation. The experimental rig is housed within an anechoic chamber allowing for clear acoustic analysis. Near field pressure measurements (embedded into the aft-deck plate) will study the local unsteadiness at the nozzle exit. Far field pressure measurements will study the general directivity of the acoustic emissions. Streamwise and cross-stream PIV, in addition to streamwise Schlieren imaging will study each configurations impact on the shock structures.