Instability wave excitation by a localized vibrator in the boundary layer

1984 ◽  
Vol 25 (6) ◽  
pp. 867-873 ◽  
Author(s):  
A. M. Tumin ◽  
A. V. Fedorov
Keyword(s):  
Boundary Layer ◽  
Instability Wave ◽  
Wave Excitation

Soft and hard wave excitation on an elastic covering in a turbulent boundary layer

1996 ◽  
Vol 38 (3-4) ◽  
pp. 137-140
Author(s):  
V. P. Reutov ◽  
G. V. Rybushkina
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Wave Excitation

Nonlinear evolution of a pair of oblique instability waves in a supersonic boundary layer

1995 ◽  
Vol 282 ◽  
pp. 339-371 ◽  
Author(s):  
S. J. Leib ◽  
Sang Soo Lee
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Nonlinear Evolution ◽  
Supersonic Boundary Layer ◽  
Inviscid Limit ◽  
Instability Wave ◽  
Neutral Stability ◽  
Mean Flow ◽  
Number Range ◽  
Instability Waves

We study the nonlinear evolution of a pair of oblique instability waves in a supersonic boundary layer over a flat plate in the nonlinear non-equilibrium viscous critical layer regime. The instability wave amplitude is governed by the same integro-differential equation as that derived by Goldstein & Choi (1989) in the inviscid limit and by Wu, Lee & Cowley (1993) with viscous effects included, but the coefficient appearing in this equation depends on the mean flow and linear neutral stability solution of the supersonic boundary layer. This coefficient is evaluated numerically for the Mach number range over which the (inviscid) first mode is the dominant instability. Numerical solutions to the amplitude equation using these values of the coefficient are obtained. It is found that, for insulated and cooled wall conditions and angles corresponding to the most rapidly growing waves, the amplitude ends in a singularity at a finite downstream position over the entire Mach number range regardless of the size of the viscous parameter. The explosive growth of the instability waves provides a mechanism by which the boundary layer can break down. A new feature of the compressible problem is the nonlinear generation of a spanwise-dependent mean distortion of the temperature along with that of the velocity found in the incompressible case.

Instability-wave propagation in boundary-layer flows at subsonic through hypersonic Mach numbers

2004 ◽  
Vol 65 (4-5) ◽  
pp. 469-487 ◽  
Author(s):  
Li Jiang ◽  
Chau-Lyan Chang ◽  
Meelan Choudhari ◽  
Chaoqun Liu
Keyword(s):  
Boundary Layer ◽  
Wave Propagation ◽  
Instability Wave ◽  
Boundary Layer Flows ◽  
Mach Numbers

Boundary Layer Receptivity Theory

1990 ◽  
Vol 43 (5S) ◽  
pp. S152-S157 ◽  
Author(s):  
E. J. Kerschen
Keyword(s):  
Boundary Layer ◽  
Wavelength Conversion ◽  
Free Stream ◽  
Asymptotic Methods ◽  
Instability Wave ◽  
Mean Flow ◽  
Theoretical Understanding ◽  
Instability Waves ◽  
Laminar Boundary Layers ◽  
The Mean

The receptivity mechanisms by which free-stream disturbances generate instability waves in laminar boundary layers are discussed. Free-stream disturbances have wavelengths which are generally much longer than those of instability waves. Hence, the transfer of energy from the free-stream disturbance to the instability wave requires a wavelength conversion mechanism. Recent analyses using asymptotic methods have shown that the wavelength conversion takes place in regions of the boundary layer where the mean flow adjusts on a short streamwise length scale. This paper reviews recent progress in the theoretical understanding of these phenomena.

Wave excitation in an unsteady boundary layer

1997 ◽  
Author(s):  
Sanford Davis ◽  
Sanford Davis
Keyword(s):  
Boundary Layer ◽  
Wave Excitation ◽  
Unsteady Boundary Layer
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