Generalized Mean-Flow Theory of Wave-Current-Bottom Interactions

1 .IntroductionAveraging has beenconsidered as anactive ,effective and precise methodinthe studyof fluid dy-namics ,andthe governing macroscopic variables like velocity are the averagingresults inthemselves .Consequently,for a special purpose ,the fluid m…

Generalized Mean-Flow Theory of Wave-Current-Bottom Interactions

The interaction between waves,currents and bottoms in estuarine and coastal regions is ubiquitious,in particular the dynamic mechanism ofwaves on large-scale slowly varying currents.The wave action concept may be extended and appli-cated to the study of the mechanism.Considering the effects of moving bottoms and starting from the Navier-Stokes equa-tion of motion of a viscous fluid including the Coriolis force,a generalized mean-flow model theory for the nearshore re-gion,that is,a set of mean-flow equations and their generalized wave action equation involving the three newkinds of ac-tions termed respectively as the currentwave action,the bottomwave action and the dissipative wave action which can be applied to arbitrary depth over moving bottoms and ambient currents with a typical vertical structure,is developed by ver-tical integration and time-averaging over a wave period,thus extending the classical concept,wave action,from the ideal averaged flow conservative system to the real averaged flow dissipative dynamical system,and having a large range of ap-plication.