Hostname: page-component-78c5997874-4rdpn Total loading time: 0 Render date: 2024-11-05T09:50:33.586Z Has data issue: false hasContentIssue false

Numerical studies of the stability of inviscid stratified shear flows

Published online by Cambridge University Press:  29 March 2006

Philip Hazel
Affiliation:
Department of Applied Mathematics and Theoretical Physics, Cambridge Present address: Computer Laboratory, Corn Exchange Street, Cambridge CB 2 3QG.

Abstract

The infinitesimal stability of inviscid, parallel, stratified shear flows to two-dimensional disturbances is described by the Taylor-Goldstein equation. Instability can only occur when the Richardson number is less than 1/4 somewhere in the flow. We consider cases where the Richardson number is everywhere non- negative. The eigenvalue problem is expressed in terms of four parameters, J a ‘typical’ Richardson number, α the (real) wavenumber and c the complex phase speed of the disturbance. Two computer programs are developed to integrate the stability equation and to solve for eigenvalues: the first finds c given α and J, the second finds α and J when c ≡ 0 (i.e. it computes the stationary neutral curve for the flow). This is sometimes, but not always, the stability boundary in the α, J plane. The second program works only for cases where the velocity and density profiles are antisymmetric about the velocity inflexion point. By means of these two programs, several configurations of velocity and density have been investigated, both of the free-shear-layer type and the jet type. Calculations of temporal growth rates for particular profiles have been made.

Type
Research Article
Copyright
© 1972 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Drazin, P. G. & Howard, L. N. 1962 J. Fluid Mech. 14, 257.
Drazin, P. G. & Howard, L. N. 1966 Advan. Appl. Math. 9, 1.
Goldstein, S. 1931 Proc. Roy. Soc. A 132, 524.
Hazel, P. 1969 Ph.D. thesis, University of Cambridge.
Holmboe, J. 1960 Lecture Notes UCLA. (Unpublished.)
Holmboe, J. 1962 Ceophys. Publ. 24, 67.
Howard, L. N. 1961 J. Fluid Mech. 10, 509.
Howard, L. N. 1964 J. Mechanique, 3, 433.
Kaplan, R. E. 1964 The Stability of Laminar Boundary Layers in the Presence of Compliant Boundaries. U.S. Office of Naval Research.
Miles, J. W. 1961 J. Fluid Mech. 10, 496.
Miles, J. W. 1963 J. Fluid Mech. 16, 209.
Scotti, R. S. 1968 Ph.D. thesis, University of California, Berkeley.
Taylor, G. I. 1931 Proc. Roy. Soc. A 132, 499.
Thorpe, S. A. 1969 J. Fluid Mech. 36, 673.