ABSTRACT
Lateral cavities adjacent to a mainstream are major storage zones of the riverine environment. The aim of present work is to develop an analytical tool that permits to predict the frequency of vortex shedding along the interface between such a lateral cavity and its mainstream, and to validate this model via laboratory experiments. We first observe that the frequency of vortex shedding and the frequency of free-surface deformation in the cavity are equal to each other. Then, to predict this frequency, an analytical model developed in the 1960’s for aeroacoustics cavities is adapted to the present hydrodynamics configuration. It consists in a coupling between two resonances: a feedback model governing the vortex dynamics of the mixing layer (also known as “Rossiter model”) and a surface deformation which shape equals a natural mode of the cavity. When adapted to the present open-channel configuration, the agreement of this coupling with the measured frequencies appears to be fair. Still, while this approach permits to explain the observed frequencies, it remains unpredictive for some configurations and will require future improvements before it can be used to optimize the geometries of man-made lateral cavity.
