CFD-Based Simulation of Inlet Unstart Phenomena: Toward Supersonic Inlet Flow Control Techniques Available to Purchase

A time-accurate, full Navier-Stokes, Computational Fluid Dynamics (CFD) analysis of a back-pressure-induced, high-speed inlet unstart event was conducted. The objective was to identify visible and quantitative flowfield characteristics prior to and during an unstart event. The CFD-based investigation was conducted on a 2-D wind-tunnel model geometry of a forebody and inlet at a freestream Mach number of 5. A sequence of steady-state solutions were run to map the inlet flowfield response to subsequent increases in back-pressure from a design value up to the point of imminent unstart. A time-accurate solution commenced, using the final steady-state solution as the initial condition. The CFD-derived inlet flowfield contour plots compared well with test-derived color schlieren images, while predictions for steady-state and transient wall pressure compared reasonably with test data. A CFD-based study of inlet flow control techniques will follow.