INFLUENCE OF CORIOLIS FORCES ON THE DYNAMIQUE OF A TURBULENT JET

Abstract. The influence of Coriolis forces is studied under realistic conditions on a jet in atmospheric medium. Under the Boussinesq approximation, the relative thickness of the jet defines a small parameter ε in the flow. This parameter governs the asymptotic expansion of the analysis. Using a linear spectral approach, two-point closure correlation equations are obtained under some realistic simplifying assumptions. The solution of these equations depends on the mean velocity field. An expansion of the solution is constructed by means of analytical tools, including the effects of several fundamental physical parameters. As application of the model, the spectral components of the solution are determined using further simplifying approximations. We exhibit some consequences of the vortex dynamics applied to a free jet submitted to Coriolis forces. The most important effect is the appearance of Kelvin-Helmoltz instabilities and the appearance of coherent vortices induced by the jet itself. The effects of the Coriolis forces on the evolution of these structures along the jet are also examined. The results are matched with other results obtained by means of numerical methods and experimental results