Dissipative-convergent intermittency in dynamics of tidal waves in estuaries

Resumo

The effect of dissipative-convergent intermittency in dynamics of tidal waves in estuaries is described. The effect manifests itself in spatial modulation of the tide amplitude. The effects of convergent channel and turbulent friction are competitive in dynamics of tidal waves in bays, gulfs, and estuaries. This manifests itself in the alternating excess of the action of one effect over another as the tidal wave penetrates deep the estuary. The effect of dissipative-convergent intermittency is manifested most completely in “strange” bays in which the mean water depth is commensurable with the Stokes layer thickness. It is shown that the spatial distribution of the tidal wave amplitude has a minimum in the convergent channel. If the minimum point lies beyond the estuary, then the effect of convergent channel predominates and the wave height increases to the vertex. If the minimum point lies in the neighborhood of the estuary vertex then the effect of turbulent friction predominates along the entire bay length and the wave height decreases to the bay vertex. Finally, if the minimum point finds itself in the middle part of the estuary, then the case of the “strange” bays arises, namely, in such bays the wave height decreases to crossing the minimum point and begins increases again after its passage. The local increase in the tidal wave amplitude can be manifested further in the mouth of the inflowing river.