Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-25T11:38:48.141Z Has data issue: false hasContentIssue false

Internal wave—vortical mode interactions in strongly stratified flows

Published online by Cambridge University Press:  26 April 2006

M. -Pascale Lelong
Affiliation:
University of Washington, Seattle WA, USA Present address: National Center for Atmospheric Research, Boulder CO 80307–3000, USA.
James J. Riley
Affiliation:
University of Washington, Seattle WA, USA

Abstract

In this paper, weakly nonlinear interactions in a strongly-stratified, inviscid flow are re-examined, taking into account the presence of both internal waves and vortical modes. We use a multiple scale formulation, based on the two characteristic times of the problem. Ertel's potential vorticity motivates a splitting of the velocity into propagating (wave) and non-propagating (vortical) contributions. We focus on the three fundamental interactions: the wave/wave, wave/vortex and vortex/vortex interactions. The oft-studied wave/wave interaction illustrates the difference between potential and vertical vorticities. We then identify two additional resonances for the wave/vortex and vortex/vortex interactions respectively. The wave/vortex resonance provides a mechanism for redistributing energy in spectral space while the vortex/vortex interaction may give rise to an internal wave field.

Type
Research Article
Copyright
© 1991 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

Bretherton, F. P. 1964 Resonant interactions between waves. J. Fluid Mech. 20, 457479.Google Scholar
Dong, B. & Yeh, K. C. 1988 Resonant and nonresonant wave-wave interactions in an isothermal atmosphere. J. Geophys. Res. 93, D4, 3729–3744.Google Scholar
Ertel, H. 1942 Ein neuer Hydrodynamischer Wirbelsatz. Met. Z. 59, 271281.Google Scholar
Gage, K. S. 1979 Evidence for a k−5/3 law inertial range in mesoscale two-dimensional turbulence. J. Atmos. Sci. 36, 19501954.Google Scholar
Gage, K. S. & Nastrom, G. D. 1988 Further discussion of the dynamical processes that contribute to the spectrum of mesoscale atmospheric motions. Preprint volume of the Eighth Symposium on Turbulence and Diffusion, San Diego, pp. 217220. American Meteorological Society, Boston.
Herring, J. R. & Métais, O. 1988 Numerical experiments in forced stably stratified turbulence. J. Fluid Mech. 202, 97115.Google Scholar
Kevorkian, J. & Cole, J. D. 1981 Perturbation Methods in Applied Mathematics. Applied Mathematical Sciences, vol. 34. Springer.
Kraichnan, R. H. 1967 Inertial ranges in two-dimensional turbulence. Phys. Fluids 10, 14171423.Google Scholar
Lilly, D. K. 1983 Stratified turbulence and the mesoscale variability of the atmosphere. J. Atmos. Sci. 40, 749761.Google Scholar
Lin, J.-T. & Pao, Y.-H. 1979 Wakes in stratified fluids. Ann. Rev. Fluid Mech. 11, 317338.Google Scholar
McComas, C. H. & Bretherton, F. P. 1977 Resonant interaction of oceanic internal waves. J. Geophys. Res. 82, 13971412.Google Scholar
Métais, O. & Herring, J. R. 1989 Numerical simulations of freely evolving turbulence in stably stratified fluids. J. Fluid Mech. 202, 117148.Google Scholar
Müller, P., Holloway, G., Henyey, F. & Pomphrey, N. 1986 Nonlinear interactions among internal waves. Rev. Geophys. 24, 493536.Google Scholar
Müller, P., Lien, R. C. & Williams, R. 1988 Estimates of potential vorticity at small scales in the ocean. J. Phys. Oceanogr. 18, 401416.Google Scholar
Phillips, 0. M. 1968 The interaction trapping of internal gravity waves. J. Fluid Mech. 34, 407416.Google Scholar
Pehillips, O. M. 1981 Wave interactions — the evolution of an idea. J. Fluid Mech. 106, 215227.Google Scholar
Riley, J. J., Metcalfe, R. W. & Weissman, M. A. 1981 Direct numerical simulations of homogeneous turbulence in density-stratified fluids. Proc. AIP Conf. on Nonlinear Properties of Internal Waves (ed. B. J. West), pp. 79112.
Staquet, C. & Riley, J. J. 1989 A numerical study of a stably-stratified mixing layer. In Turbulent Shear Flows, vol. 6 (ed. J.-C. André, J. Cousteix, F. Durst, B. E. Launder, F. W. Schmidt & J. H. Whitelaw), pp. 381397. Springer.
Staquet, C. & Riley, J. J. 1990 On the velocity field associated with potential vorticity. Dyn. Atmos. Oceans 14, 93123.Google Scholar