The effect of Mach number on the stability of a plane supersonic wake
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (USA)
- Department of Aeronautics and Astronautics, Stanford University, Stanford, CA (USA)
- NASA/Ames Research Center, Moffett Field, CA (USA)
Recent interest in supersonic combustion and problems of transatmospheric flight has prompted renewed research efforts in laminar--turbulent free-shear flow transition. In the present work, the influence of Mach number on the stability of supersonic planar wake flows is investigated to gain insight into the physics of linear, nonlinear, and three-dimensional (3-D) stages of transition. The effect of varying the relative phase difference between a fundamental instability mode and its subharmonic is investigated as a possible means of controlling the evolution of a wake. From a linear stability analysis, it is found that the influence of increasing Mach number is stabilizing, resulting in a growth rate at a Mach number of 3 which is 60% that of an incompressible wake. Direct numerical simulations of the time-dependent compressible Navier--Stokes equations in two and three dimensions are performed for a forced time-developing wake using a spectral collocation method. The results of the two-dimensional (2-D) simulations show the slow rollup of spanwise vortices at high Mach numbers that is attributed to the influence of baroclinic and dilatational effects. Finally, the results of three-dimensional simulations forced with the most unstable Kelvin--Helmholtz wave and a pair of oblique three-dimensional waves show that, depending on the initial phasing between the 2-D and 3-D waves, vortex loops may or may not form as a result of the interaction between the streamwise and spanwise vorticity.
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6741730
- Journal Information:
- Physics of Fluids A; (USA), Journal Name: Physics of Fluids A; (USA) Vol. 2:6; ISSN 0899-8213; ISSN PFADE
- Country of Publication:
- United States
- Language:
- English
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