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Experiments on periodically forced flow over topography in a rotating fluid

Published online by Cambridge University Press:  26 April 2006

John M. Pratte
Affiliation:
Department of Astrophvsical, Planetary and Atmospheric Sciences, University of Colorado Boulder, CO 80309, USA
J. E. Hart
Affiliation:
Department of Astrophvsical, Planetary and Atmospheric Sciences, University of Colorado Boulder, CO 80309, USA

Abstract

Results from laboratory experiments on oscillatory flows over topograph in a rapidly rotating cylinder of homogeneous liquid are presented and compared with weakly nonlinear and low-order theories. With periodic forcing, the motion can be either periodic or chaotic. In the periodic regime, linear Rossby waves excited by the sloshing flow over shallow bottom topography become resonant at forcing frequencies that are integer multiples of the natural free Rossby wave frequency. As the topographic effect or the forcing amplitude is increased, the maximum response is shifted away from the linearly resonant frequency; to higher periods for azimuthal topographic wavenumbers of 1 and to lower periods for topographic zonal wavenumbers exceeding 1, in agreement with theory. The simple theories which use slippery sidewalk do not describe the observed chaotic flows. These complex states are associated with the development of small-scale vortices in the sidewall boundary layer that are shed into the interior. For both periodic and chaotic flows, long-time particle paths can contain significant chaotic components which are revealed in direct Poincaré sections constructed from observations of surface floats.

Type
Research Article
Copyright
© 1991 Cambridge University Press

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References

Audunson, T. & Gebhart, B. 1976 Secondary mean motions arising in a buoyancy induced flow. Intl J. Heat Mass Transfer 19, 737.Google Scholar
Brewster, R. A. 1988 Experimental studies of natural convection effects on downward freezing of cold pure and saline water, and stability of mixed convection flow adjacent to a vertical isothermal surface. Ph.D. dissertation, University of Pennsylvania. Philadelphia, Pennsylvania.
Carey, V. P. & Gebhart, B. 1982 Transport at large downstream distances in mixed convection flow adjacent to a vertical uniform-heat-flux surface. Intl J. Heat Mass Transfer 25, 255.Google Scholar
Carey, V. P. & Gebhart, B. 1983 The stability and disturbance amplification characteristics of vertical mixed convection flow. J. Fluid Mech. 127, 185.Google Scholar
Chen, T. S. & Moutsoglou, A. 1979 Wave instability of mixed convection flow on inclined surfaces. Numer. Heat Transfer 2, 497.Google Scholar
Chen, T. S. & Mucoglu, A. 1979 Wave instability of mixed convection over a horizontal flat plate. Intl J. Heat Mass Transfer 22, 185.Google Scholar
Dring, R. P. & Gebhart, B. 1968 A theoretical investigation of disturbance amplification in external laminar natural convection flow. J. Fluid Mech. 34, 551.Google Scholar
Eckert, E. R. G. & Soehngen, E. 1951 Interferometric studies on the stability and transition to turbulence in a free-convection boundary-layer. Proc. Gen. Disc. Heat Transfer, ASME and IME, London, pp. 321.
Eshghy, S. 1964 Forced-flow effects on free-convection flow and heat transfer. Trans. ASME C: J. Heat Transfer 86, 290.Google Scholar
Gaster, M. 1974 On the effects of boundary-layer growth on flow stability. J. Fluid Mech. 66, 465.Google Scholar
Gebhart, B., Jaluria, Y., Mahajan, R. L. & Sammakia, B. 1988 Buoyancy-Induced Flows and Transport. Hemisphere.
Hieber, C. A. & Gebhart, B. 1971 Stability of natural convection boundary layers: some numerical solutions. J. Fluid Mech. 48, 625.Google Scholar
Jaluria, Y. & Gebhart, B. 1974 On transition mechanisms in vertical natural convection flow. J. Fluid Mech. 66, 309.Google Scholar
Knowles, C. P. & Gebhart, B. 1968 The stability of the laminar natural convection boundary layer. J. Fluid Mech. 34, 657.Google Scholar
Krishnamurthy, R. & Gebhart, B. 1989 An experimental study of transition to turbulence in vertical mixed convection flows. Trans. ASME C: J. Heat Transfer 111, 121.Google Scholar
Lee, S. L., Chen, T. S. & Armaly, B. F. 1987a Free stream effects on the wave instability of buoyant flows along an isothermal vertical flat plate. Intl J. Heat Mass Transfer 30, 1556.Google Scholar
Lee, S. L., Chen, T. S. & Armaly, B. F. 1987b Wave instability characteristics for the entire regime of mixed convection flow along vertical flat plates. Intl J. Heat Mass Transfer 30, 1743.Google Scholar
Lee, S. L., Chen, T. S. & Armaly, B. F. 1988 Non-parallel wave instability of mixed convection flow on inclined flat plates. Intl J. Mass Transfer 31, 1385.Google Scholar
Lin, C. C. 1945 On the stability of two-dimensional parallel flows. Part II — Stability in an inviscid fluid. Q. Appl. Maths 3, 218.Google Scholar
Merkin, J. H. 1969 The effect of buoyancy on the boundary-layer flow over a semi-infinite vertical flat plate in a uniform free stream. J. Fluid Mech. 35, 439.Google Scholar
Mucoglu, A. & Chen, T. S. 1978 Wave instability of mixed convection flow along a vertical flat plate. Numer. Heat Transfer 1, 267.Google Scholar
Mucoglu, A. & Chen, T. S. 1979 Mixed convection on inclined surfaces, Trans. ASME C: J. Heat Transfer 101, 422.Google Scholar
Szewczyk, A. A. 1964 Combined forced and free-convection laminar flow. Trans. ASME C: J. Heat Transfer 86, 501.Google Scholar
Wakitani, S. 1985 Non-parallel-flow stability of a two-dimensional buoyant plume. J. Fluid Mech. 159, 241.Google Scholar