Characteristics of nonlinear evolution of wavepackets in boundary layers

2013 ◽  
Vol 56 (2) ◽  
pp. 250-256 ◽  
Author(s):  
Min Yu ◽  
JiSheng Luo ◽  
Jia Li
Keyword(s):  
Boundary Layers ◽  
Nonlinear Evolution

The production of subharmonic waves in the nonlinear evolution of wavepackets in boundary layers

1999 ◽  
Vol 399 ◽  
pp. 301-318 ◽  
Author(s):  
MARCELLO A. F. MEDEIROS ◽  
MICHAEL GASTER
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Nonlinear Interaction ◽  
Strong Influence ◽  
Nonlinear Evolution ◽  
Nonlinear Behaviour ◽  
Two Dimensional ◽  
Tollmien Schlichting ◽  
Acoustic Excitations ◽  
Dimensional Wave

The nonlinear evolution of wavepackets in a laminar boundary layer has been studied experimentally. The packets were generated by acoustic excitations injected into the boundary layer through a small hole in the plate. Various packets with different phases relative to the envelope were studied. It was found that for all the packets the nonlinearity involved the appearance of oblique modes of frequency close to the subharmonic of the dominant two-dimensional wave. Moreover, the results confirmed that the phase had a strong influence on the strength of the nonlinear interaction. The experimental observations also indicated that although a subharmonic resonance appeared to be present in the process, it alone could not explain the nonlinear behaviour. The experiment demonstrated that the process must also involve a mechanism that generates oblique waves of frequency lower than the Tollmien–Schlichting band.

scholarly journals On Nonlinear Evolution of C-type Instability in Nonparallel Boundary Layers

2007 ◽  
Vol 20 (4) ◽  
pp. 313-319 ◽  
Author(s):  
Jixue Liu ◽  
Dengbin Tang ◽  
Yingzhao Yang
Keyword(s):  
Boundary Layers ◽  
Nonlinear Evolution

Nonlinear evolution and breakdown in unstable boundary layers

1980 ◽  
Vol 99 (2) ◽  
pp. 247-265 ◽  
Author(s):  
A. D. D. Craik
Keyword(s):  
Boundary Layer ◽  
Laminar Flow ◽  
Flat Plate ◽  
Boundary Layers ◽  
Nonlinear Evolution ◽  
Secondary Instability ◽  
Nonlinear Instability ◽  
Weakly Nonlinear ◽  
Theory And Experiment

The nonlinear evolution and breakdown of laminar flow in the boundary layer on a flat plate is examined with the aim of making a closer comparison of theory and experiment than has been attempted previously. The importance of three-dimensionality is emphasized. It is concluded that many features of the nonlinear instability are consistent with existing linear and weakly nonlinear theories even as breakdown is approached. The development of the secondary instability, or ‘spike’, is also considered and suggestions for an improved theory of its growth are made.

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