Receptivity of secondary instability modes in streaky boundary layers

2018 ◽  
Vol 30 (11) ◽  
pp. 114102 ◽  
Author(s):  
Anyong Zhang ◽  
Ming Dong ◽  
Yongming Zhang
Keyword(s):  
Boundary Layers ◽  
Secondary Instability ◽  
Instability Modes

Secondary instability of cross-flow vortices in Falkner–Skan–Cooke boundary layers

1998 ◽  
Vol 368 ◽  
pp. 339-357 ◽  
Author(s):  
MARKUS HÖGBERG ◽  
DAN HENNINGSON
Keyword(s):  
Growth Rate ◽  
Shear Layer ◽  
Boundary Layers ◽  
Growth Rates ◽  
High Frequency ◽  
Cross Flow ◽  
Low Frequency ◽  
Secondary Instability ◽  
The Cross ◽  
Flow Vortex

Linear eigenvalue calculations and spatial direct numerical simulations (DNS) of disturbance growth in Falkner–Skan–Cooke (FSC) boundary layers have been performed. The growth rates of the small-amplitude disturbances obtained from the DNS calculations show differences compared to linear local theory, i.e. non-parallel effects are present. With higher amplitude initial disturbances in the DNS calculations, saturated cross-flow vortices are obtained. In these vortices strong shear layers appear. When a small random disturbance is added to a saturated cross-flow vortex, a low-frequency mode is found located at the bottom shear layer of the cross-flow vortex and a high-frequency secondary instability is found at the upper shear layer of the cross-flow vortex. The growth rates of the secondary instabilities are found from detailed analysis of simulations of single-frequency disturbances. The low-frequency disturbance is amplified throughout the domain, but with a lower growth rate than the high-frequency disturbance, which is amplified only once the cross-flow vortices have started to saturate. The high-frequency disturbance has a growth rate that is considerably higher than the growth rates for the primary instabilities, and it is conjectured that the onset of the high-frequency instability is well correlated with the start of transition.

Secondary instability mechanisms in compressible axisymmetric boundary layers

AIAA Journal ◽  
1993 ◽  
Vol 31 (9) ◽  
pp. 1605-1610 ◽  
Author(s):  
Lian L. Ng ◽  
Thomas A. Zang
Keyword(s):  
Boundary Layers ◽  
Secondary Instability

Instability Modes in Boundary Layers of an Inclined Cone at Mach 6

2014 ◽  
Vol 51 (2) ◽  
pp. 442-454 ◽  
Author(s):  
Federico Muñoz ◽  
Dirk Heitmann ◽  
Rolf Radespiel
Keyword(s):  
Boundary Layers ◽  
Instability Modes
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