Hostname: page-component-cb9f654ff-d5ftd Total loading time: 0 Render date: 2025-08-23T14:35:01.507Z Has data issue: false hasContentIssue false
  • English
  • Français

Barotropic quasi-geostrophic f-planeflow over anisotropic topography

Published online by Cambridge University Press:  26 April 2006

G. F. Carnevale ,
R. Purini ,
P. Orlandi  and
P. Cavazza
G. F. Carnevale
Affiliation:
Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
R. Purini
Affiliation:
Istituto di Fisica dell'Atmosfera, P.le Luigi Sturzo 31, 00144 Roma, Italy
P. Orlandi
Affiliation:
Dipartimento di Meccanica e Aeronautica, Universita di Roma, “La Sapienza,” Via Eudossiana 16, 00184 Roma, Italy
P. Cavazza
Affiliation:
Dipartimento di Meccanica e Aeronautica, Universita di Roma, “La Sapienza,” Via Eudossiana 16, 00184 Roma, Italy
Get access Rights & Permissions [Opens in a new window]

Abstract

For an anisotropic topographic feature in a large-scale flow, theorientation of the topography with respect to the flow will affectthe vorticity production that results from the topography–flowinteraction. This in turn affects the amount of form drag that theambient flow experiences. Numerical simulations and perturbationtheory are used to explore these effects of change in topographicorientation. The flow is modelled as a quasi-geostrophic homogeneousfluid on an f-plane. The topography is taken to bea hill of limited extent, with an elliptical cross-section in thehorizontal. It is shown that, as a result of a basic asymmetry ofthe quasi-geostrophic flow, the strength of the form drag dependsnot only on the magnitude of the angle that the topographic axismakes with the oncoming stream, but also on the sign of this angle.For sufficiently low topography, it is found that a positive angleof attack leads to a stronger form drag than that for thecorresponding negative angle. For strong topography, this relationis reversed, with the negative angle then resulting in the strongerform drag.

Information

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 285 , 25 February 1995 , pp. 329 - 347
Copyright
© 1995 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.)

Article purchase

Temporarily unavailable

References

Bannon, P. R. 1980 Rotating barotropic flow over finite isolated topography. J. Fluid Mech. 101, 281–306.Google Scholar
Bannon, P. R. 1985 Flow acceleration and mountain drag. J. Atmos. Sci. 42, 2445–2453.Google Scholar
Batchelor, G. K. 1967 An Introduction to Fluid Dynamics. Cambridge University Press.Google Scholar
Boyer, D. L. 1971 Rotating flow over long shallow ridges. Geophys. Fluid Dyn. 2, 165–183.Google Scholar
Carnevale, G. F. & Frederiksen, J. S. 1987 Nonlinear stability and statistical mechanics of flow over topography. J. Fluid Mech. 175, 157–181.Google Scholar
Cook, K. H. & Held, I. M. 1992 The stationary response to large-scale oragraphy in a general circulation model and a linear model. J. Atmos. Sci. 49, 525–539.Google Scholar
Hart, J. E. 1979 Barotropic quasi-geostrophic flow over anisotropic mountains. J. Atmos. Sci. 36, 1736–1746.Google Scholar
Huppert, H. E. & Bryan, K. 1976 Topographically generated eddies. Deep-Sea Res. 23, 655–679.Google Scholar
Johnson, E. R. 1978 Trapped vortices in rotating flow. J. Fluid Mech. 86, 209–224.Google Scholar
Merkine, L. & Kalnay-Rivas, E. 1976 Rotating stratified flow over finite isolated topography. J. Atmos. Sci. 33, 908–922.Google Scholar
Orlanski, I. 1976 A simple boundary condition for unbounded hyperbolic flows. J. Comput. Phys. 21, 251–269.Google Scholar
Pedlosky, J. 1987 Geophysical Fluid Dynamics, 2nd Edn. Springer.CrossRefGoogle Scholar
Pierrehumbert, R. T. & Malguzzi, P. 1984 Forced coherent structures and local multiple equilibria in a barotropic atmosphere. J. Atmos. Sci. 41, 246–257.Google Scholar
Verron, J. & Le Provost, C. 1985 A numerical study of quasi-geostrophic flow over isolated topography. J. Fluid Mech. 154, 231–252.Google Scholar