Upstream internal solitons generated by moving disturbances

Abstract

Here we study the phenomenon of internal solitons generated periodically by a two-dimensional disturbance moving through a stratified fluid with a constant transcritical velocity. Experimentally, with a topography moving along the floor of a fluid layer as forcing disturbance, we found that every so often, a new internal solitary wave was generated to propagate ahead of the disturbance, forming in time a procession of upstream-moving solitons. The amplitude and period of generation of the solitons depend on the Froude number, the density stratification and forcing distribution. Theoretical predictions are made numerically based on the inhomogeneous Boussinesq model (IB) and the forced KdV model (IKdV). Broad agreement was found between theory and experiment.