On the nonlinear evolution of wind-driven gravity waves

A. Alexakis, A. C. Calder, L. J. Dursi, R. Rosner, J. W. Truran, B. Fryxell, M. Zingale, Francis Timmes, K. Olson, P. Ricker

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

We present a study of wind-driven nolinear interfacial gravity using numerical simulations in two dimensions. We consider a case relevant to mixing phenomenon in astrophysical events such as novae in which the density ratio is approximately 1:10. Our physical setup follows the proposed mechanism of Miles [J. Fluid Mech. 3, 185 (1957)] for the amplification of such waves. Our results show good agreement with linear predictions for the growth of the waves. We explore how the wind strength affects the wave dynamics and the resulting mixing in the nonlinear stage. We identify two regimes of mixing, namely, the overturning and the cusp-breaking regimes. The former occurs when the wind is strong enough to overcome the gravitational potential barrier and overturn the wave. This result is in agreement with the common notion of turbulent mixing in which density gradients are increased to diffusion scales by the stretching of a series of vortices. In the latter case, mixing is the result of cusp instabilities. Although the wind is not strong enough to overturn the wave in this case, it can drive the wave up to a maximum amplitude where a singular structure at the cusp of the wave forms. Such structures are subject to various instabilities near the cusp that result in breaking the cusp. Mixing then results from these secondary instabilities and the spray-like structures that appear as a consequence of the breaking.

Original languageEnglish (US)
Pages (from-to)3256-3268
Number of pages13
JournalPhysics of Fluids
Volume16
Issue number9
DOIs
StatePublished - Sep 2004
Externally publishedYes

Fingerprint

Gravity waves
gravity waves
cusps
linear prediction
novae
turbulent mixing
gravitational fields
Stretching
sprayers
Amplification
astrophysics
Gravitation
Vortex flow
vortices
gravitation
gradients
Fluids
fluids
Computer simulation

ASJC Scopus subject areas

  • Mechanics of Materials
  • Computational Mechanics
  • Physics and Astronomy(all)
  • Fluid Flow and Transfer Processes
  • Condensed Matter Physics

Cite this

Alexakis, A., Calder, A. C., Dursi, L. J., Rosner, R., Truran, J. W., Fryxell, B., ... Ricker, P. (2004). On the nonlinear evolution of wind-driven gravity waves. Physics of Fluids, 16(9), 3256-3268. https://doi.org/10.1063/1.1771695

On the nonlinear evolution of wind-driven gravity waves. / Alexakis, A.; Calder, A. C.; Dursi, L. J.; Rosner, R.; Truran, J. W.; Fryxell, B.; Zingale, M.; Timmes, Francis; Olson, K.; Ricker, P.

In: Physics of Fluids, Vol. 16, No. 9, 09.2004, p. 3256-3268.

Research output: Contribution to journalArticle

Alexakis, A, Calder, AC, Dursi, LJ, Rosner, R, Truran, JW, Fryxell, B, Zingale, M, Timmes, F, Olson, K & Ricker, P 2004, 'On the nonlinear evolution of wind-driven gravity waves', Physics of Fluids, vol. 16, no. 9, pp. 3256-3268. https://doi.org/10.1063/1.1771695
Alexakis A, Calder AC, Dursi LJ, Rosner R, Truran JW, Fryxell B et al. On the nonlinear evolution of wind-driven gravity waves. Physics of Fluids. 2004 Sep;16(9):3256-3268. https://doi.org/10.1063/1.1771695
Alexakis, A. ; Calder, A. C. ; Dursi, L. J. ; Rosner, R. ; Truran, J. W. ; Fryxell, B. ; Zingale, M. ; Timmes, Francis ; Olson, K. ; Ricker, P. / On the nonlinear evolution of wind-driven gravity waves. In: Physics of Fluids. 2004 ; Vol. 16, No. 9. pp. 3256-3268.
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