Unstart of a Hypersonic Inlet with Side Compression Caused by Downstream Choking

A hypersonic inlet with side compression has been tested at a freestream Mach number of 6.0 to enrich the understandings of hypersonic inlet unstart. A flow plug is placed at the duct exit to simulate the combustion induced high pressure and to initiate the inlet unstart. High-speed schlieren imaging and time-resolved pressure measurements are used simultaneously to record the unsteady flow structures and surface pressures of the unstart process. The inlet operates in a big buzz mode with a base frequency of 30 Hz and exhibits a series of unsteady flow patterns similar to those of rectangular hypersonic inlets in a buzz cycle when the throttling ratio is 87.4%. During the upstream propagating process of the unstart shock system, the propagation velocity in the two ends of the duct is higher than that in the middle section of the duct, with a minimum value around the isolator. Once the separation bubble induced oblique shock is expelled over the cowl lip, a supersonic reverse flow with a Mach number of 1.5...

[1]  H. Tan,et al.  Oscillatory Flows of Rectangular Hypersonic Inlet Unstart Caused by Downstream Mass-Flow Choking , 2009 .

[2]  David Van Wie,et al.  HyCAUSE Flight Test Program , 2008 .

[3]  H. Tan,et al.  Experimental Investigation of the Unstart Process of a Generic Hypersonic Inlet , 2011 .

[4]  Sébastien Deck,et al.  Delayed Detached-Eddy Simulation and Analysis of Supersonic Inlet Buzz , 2008 .

[5]  In-Seuck Jeung,et al.  Flow Characteristics of Small-Sized Supersonic Inlets , 2011 .

[6]  Scott D. Holland.  Wind-tunnel blockage and actuation systems test of a two-dimensional scramjet inlet unstart model at Mach 6 , 1994 .

[7]  J. Wagner,et al.  Experimental Investigation of Unstart in an Inlet/Isolator Model in Mach 5 Flow , 2009 .

[8]  J. Wagner,et al.  Velocimetry measurements of unstart in an inlet-isolator model in Mach 5 flow , 2010 .

[9]  Carl A. Trexler,et al.  Performance of an inlet for an integrated scramjet concept , 1974 .

[10]  Sébastien Deck,et al.  Experimental Study of Supersonic Inlet Buzz , 2006 .

[11]  Pong-Jeu Lu,et al.  Numerical Investigation of Inlet Buzz Flow , 1998 .

[12]  H. Tan,et al.  Experimental Study of the Unstable-Unstarted Condition of a Hypersonic Inlet at Mach 6 , 2007 .

[13]  J. Qin,et al.  Novel Oscillatory Patterns of Hypersonic Inlet Buzz , 2012 .

[14]  C R McClinton,et al.  Airbreathing Hypersonic Technology Vision Vehicles and Development Dreams , 1999 .

[15]  Takashi Shimura,et al.  LOAD OSCILLATIONS CAUSED BY UNSTART OF HYPERSONIC WIND TUNNELS AND ENGINES , 1998 .

[16]  Pierre Sagaut,et al.  Time-Frequency Analysis and Detection of Supersonic Inlet Buzz , 2007 .

[17]  Saied Emami,et al.  Unsteady pressure behavior in a ramjet/scramjet inlet , 1996 .

[18]  R. Newsome,et al.  Numerical Simulation of Near-Critical and Unsteady, Subcritical Inlet Flow , 1984 .

[19]  A. Roudakov,et al.  CIAM/NASA Mach 6.5 Scramjet Flight and Ground Test , 1999 .

[20]  Jiming Yang,et al.  Unsteady Behaviors of a Hypersonic Inlet Caused by Throttling in Shock Tunnel , 2013 .