2009/05/13 by J. L. Wagner, Justin L. Wagner, K. B. Yuceil +7 · 340 citations
Engineering · #Acoustics #Aerodynamics and Acoustics in Jet Flows #Boundary layer #Combustor #Computational Fluid Dynamics and Aerodynamics #Electrical engineering #Engineering #Fluid Dynamics and Turbulent Flows #Inlet #Isolator #Mach number #Materials science #Mechanical engineering #Mechanics #Optics #Physics #Scramjet
paper · doi:10.2514/1.40966
published in AIAA Journal 47(6), 1528-1542 (American Institute of Aeronautics and Astronautics)
openalex publication_date 2009/05/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
DOI: 10.2514/1.40966 The dynamics of unstart of a floor-mounted inlet/isolator model in a Mach 5 flow are investigated experimentally. The inlet section contains a 6-deg compression ramp, and the isolator is a rectangular straight duct that is 25.4-mm high by 50.8-mm wide by 242.3-mm long. Measurements made include 8-kHz schlieren imaging and simultaneous fast-response wall pressures along the length of the inlet/isolator. Unstart is initiated by deflecting a flap at the downstream end of the isolator. The shock system, induced by unstart, initially propagates upstream through the isolator at a velocity of about 35 m=s (in the laboratory frame of reference), then decelerates to about 20 m=s near the isolator entrance, and then accelerates to a velocity of about 74 m=s within the inlet. Throughout the isolator, unstart is seen to be strongly associated with boundary-layer separation. Once the inlet has unstarted, a highamplitudeoscillatory(periodic)unstarted flowensues,forwhichtheoscillationfrequencyisabout124Hz.However, under some conditions, an 84-Hz oscillatory unstarted flow mode, with lower pressure fluctuations, is observed. Under other conditions, a nonoscillatory unstarted flow, with much lower pressure fluctuations, is observed.