Computational and Experimental Study of Plume and Shock Interaction Effects on Sonic Boom in the NASA Ames 9x7 Supersonic Wind Tunnel

Abstract

A wind tunnel test was performed in the NASA Ames 9x7 Supersonic Wind Tunnel focusing on the shock waves traveling through and interacting with an exhaust nozzle plume. This experimental study was conducted to develop and validate the CFD capability required to accurately include nozzle flow with impinging shock effects on near field and ground-propagated sonic boom signatures. The model was made to be generic, and included a simple nozzle shape, two different aft decks, and a few generic horizontal tails. High pressure air was pumped through a nozzle at various nozzle pressure ratios (NPR) to represent the engine plume in flight. The three different aft body representations each created a different shock wave signature that passed through the plume. An aft deck configuration, where part of the aircraft shields the nozzle plume, was also tested. Retroreflective Background-Oriented Schlieren (RBOS) was used to obtain schlieren images of the flow field around the model and behind the model. This study compares wind tunnel data and numerical simulations conducted by the NASA Tetrahedral Unstructured Software System CFD code, USM3D.

Cartesian Mesh Simulations for the Third AIAA Sonic Boom Prediction Workshop

“…SBPW3 presents two near-field CFD cases: a shock-plume interaction and a complex, full-aircraft geometry with multiple inflow and outflow boundary conditions. The biconvex case is based on previous NASA wind tunnel tests [21][22][23] and CFD analysis [24,25]. Not coincidentally, the orientation of the wing and nozzle is representative of control surfaces and engine exhaust plumes at the aft end of an aircraft.…”