WAVE CURRENT INTERACTIONS AND WAVE-BLOCKING PREDICTIONS USING NHWAVE MODEL

Wave blocking in river inlets is examined using the NHWAVE (Non-Hydrostatic Wave) model under development. Blocking flows at river inlets are a significant hazard to navigation. Refractive and shoaling effects contribute to the enhancement of wave field energy, causing instabilities and breaking, resulting in energy dissipation and transfer at the blocking point. The non-linearity of wave-current interactions and wave breaking makes the dynamics of blocking flows difficult to model. Current efforts to use wave-averaged models are insufficient to describe the complex dynamics that occur within one or two wavelengths of a blocking point. NHWAVE uses the non-hydrostatic, incompressible Navier-Stokes equations to model fully dispersive wave processes in the time domain. Monochromatic wave cases are explored and compared with lab experiments of energy dissipation due to wave breaking under conditions of strong opposing current, conducted in 2002 at the University of Delaware by A. Chawla and T. J. Kirby. The model was initially unable to resolve the boundary conditions necessary to model wave blocking in a tank domain. However, developments to the numerical scheme in NHWAVE have advanced its capability in this regard. Due to the difficulties of modeling the dynamics of wave blocking and the boundary conditions in a wave tank, only preliminary results were obtained. NHWAVE needs further development; it shows promise, however, to be able to predict wave reflection, blocking, and dissipation on a strong opposing current.http://archive.org/details/wavecurrentinter1094532857Lieutenant, United States Nav