Effect of small amplitude wall waviness upon the stability of the laminar boundary layer

1976 ◽  
Vol 19 (4) ◽  
pp. 510 ◽  
Author(s):  
Martin Lessen ◽  
Santu T. Gangwani
Keyword(s):  
Boundary Layer ◽  
Laminar Boundary Layer ◽  
Small Amplitude ◽  
The Stability

The Laminar Boundary Layer on a Hot Cylinder Fixed in a Fluctuating Stream

1961 ◽  
Vol 28 (3) ◽  
pp. 339-346 ◽  
Author(s):  
R. J. Gribben
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Laminar Boundary Layer ◽  
Small Amplitude ◽  
External Flow ◽  
Low Speed ◽  
Boundary Layer Equations ◽  
Special Cases ◽  
Exact Calculations ◽  
Small Amplitude Oscillation

The equations for nonsteady, two-dimensional low-speed compressible flow in the laminar boundary layer are solved approximately by use of the Pohlhausen technique with the assumption of quartic profiles for the velocity and temperature. The external flow considered is of the form of a steady basic velocity with a superimposed small amplitude oscillation such as may arise, for example, when a sound wave is present in a uniform incident stream. The analysis is then applicable to the case of a hot cylinder fixed in such a stream. Terms of the order of the incident stream Mach number are neglected in the expressions for external flow quantities (whereas the low-speed boundary-layer equations involve errors of the order of only the square of this Mach number). Two special cases are worked out—the flow over a flat plate for which there is fair agreement with available exact calculations, and the flow over a circular cylinder.

Note on the stability of a boundary layer on a concave wall with suction

1972 ◽  
Vol 52 (2) ◽  
pp. 269-272 ◽  
Author(s):  
Ryoji Kobayashi
Keyword(s):  
Boundary Layer ◽  
Growth Factors ◽  
Laminar Boundary Layer ◽  
Critical Values ◽  
Permeable Wall ◽  
Neutral Stability ◽  
Momentum Thickness ◽  
Longitudinal Vortices ◽  
Concave Wall ◽  
The Stability

The purpose of this paper is to consider theoretically how the homogeneous suction from a slightly concave permeable wall will affect the instability of the laminar boundary layer to the onset of longitudinal vortices. The curves of neutral stability and of several growth factors of the vortices are given. The critical values of the Görtler parameter Gc, and the wavenumber σc, based on the momentum thickness of the boundary layer, are found: Gc = 1·17 and σc = 0·22.

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