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Accueil > Grands équipements > La plateforme tournante Coriolis > Projets de recherche > Archives 2006

Orographically generated nonlinear waves in rotating and non-rotating two-layer flow

E. R. Johnson, J.G. Esler, O. J. Rump, J. Sommeria, and G. G. Vilenski, Proc. R. Soc. A, 462, 3-20, 2006

This paper reports experimental observations of finite amplitude interfacial waves forced by a surface-mounted obstacle towed through a two-layer fluid both when the fluid is otherwise at rest and when the fluid is otherwise rotating as a solid body. The experimental apparatus is sufficiently wide so that sidewall effects are negligible even in near-critical flow when the towing speed is close to the interfacial long-wave speed and the transverse extent of the forced wavefield is large. The observations are modelled by a simple forced Benjamin–Davis–Acrivos equation and comparison between integrations of both linear and nonlinear problems shows the fundamental nonlinearity of the nearcritical flow patterns. In both the experiments and integrations rotation strongly confines the wavefield to extend laterally over distances only of order of the Rossby radius and also introduces finite-amplitude sharply pointed lee waves in supercritical flow.