Experimental determination of zonal winds driven by tides.
We describe a new phenomenon of zonal wind generation by tidal forcing. Following a recent theoretical and numerical analysis [A. Tilgner, Phys. Rev. Lett. 99, 194501 (2007)], we present the first experimental evidence that the nonlinear self-interaction of a tidally forced inertial mode can drive an intense axisymmetric flow in a rotating deformed sphere. Systematic measurements of zonal flows are carried out by an embarked system of particle image velocimetry, allowing the determination of general scaling laws. These results are fully relevant for zonal winds generation in planets and stars, and illustrate a generic mechanism of geostrophic flow generation by periodic forcing.
Morize
C
C
Institut de Recherche sur les Phénomènes Hors Equilibre, UMR 6594, CNRS et Aix-Marseille Universités, 49 rue F. Joliot-Curie, Boîte Postale 146, 13384 Marseille Cedex 13, France.
Le Bars
M
M
Le Gal
P
P
Tilgner
A
A