Flowfield Imaging Laboratory

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investigation of unsteadiness of shock-induced separated flows

Current: Yongxi Hou, Pablo Bueno, Noel T. Clemens and David S. Dolling
Alumni: Roderick G. Austin, Steven J. Beresh, Mark Comninos and Stephen C. Chan

shock/boundary layer structure

The study of shock wave/turbulent boundary layer interactions is important in aerodynamic design due to the large fluctuating temperatures and pressures created by the unsteady motion of the separation shock. A typical interaction can be modeled in the laboratory by simplified bodies, such as the unswept compression ramp illustrated in the schematic above. The separation shock wave is displaced from the base of the ramp and moves back and forth in a random fashion. As a result of the large adverse pressure gradient across the shock, a separation bubble forms just behind it and expands and contracts in randem with the shock motion.

This investigation aims to understand the source of the shock motion through the use of two laser imaging techniques, planar laser scattering (PLS) from an alcohol fog and particle image velocimetry (PIV).

Results from:

1. PLS and PIV in Mach 5 flow

2. Multi-Laser Multi-Camera PIV in Mach 2 flow


Publications:

  • Wide-Field PIV Study of Shock-Induced Turbulent Boundary Layer Separation, Hou, Y. X., Clemens, N. T. and Dolling, D. S., AIAA Paper 2003-0441, January 2003.
  • Relationship Between Upstream Turbulent Boundary - Layer Velocity Fluctuations and Separation Shock Unsteadiness, Beresh, S.J., Clemens, N.T. and Doling, D.S., AIAA Journal , Vol. 40, No. 12, December 2002.
  • The relationship between upstream turbulent boundary layer velocity fluctuations and separation shock unsteadiness, Beresh, S.J., Clemens, N.T., and Dolling, D.S., AIAA 99-0295, 37th Aerospace Sciences Meeting, 1999.
  • The effects of the incoming turbulent boundary layer structure on a shock-induced separated flow, Beresh, S.J., Comninos, M., Clemens, N.T., and Dolling, D.S., AIAA 98-0620, 36th Aerospace Sciences Meeting, 1998.
  • Investigation of the causes of large-scale unsteadiness of shock-induced separated flow using laser imaging, Beresh, S.J., Clemens, N.T., Dolling, D.S. and Comninos, M., AIAA 97-0064, 35th Aerospace Sciences Meeting, 1997.
  • Large-scale structure evolution in supersonic interacting shear layers, Clemens, N.T., Petullo, S.P. and Dolling, D.S., AIAA Journal (34), 1996.
  • Flowfield imaging of unsteady, separated compression ramp interactions, Chan, S.C., Clemens, N.T. and Dolling, D.S., AIAA 95-2195, 26th AIAA Fluid Dynamics Conference, 1995.

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