Abstract
When surface gravity waves propagate from a region of still water into a region of streaming water, changes occur in their characteristics. These wave characteristics have a direct implication regarding such physical phenomena as sediment movement in the near shore and coastal zone areas, energy propagation through tidal inlets into bays and estuaries, and safety to navigation as strong ebb currents can be created by channel dredging and jetty construction. The velocity field of the wave motion interacts with the velocity distribution of the current pattern and it has previously been shown analytically that the rate of energy propagation occurs at the group celerity of the wave motion and the current velocity plus additional terms produced by this Interaction. An experimental study was conducted at the U. S. Army, Corps of Engineers, Waterways Experiment Station, Vicksburg, Mississippi, into the manner in which nonuniform currents affect the characteristics of a superimposed surface gravity wave train. The work was conducted in a three-dimensional wave basin in which was simulated a tidal inlet through which could be created nonuniform currents in both an ebb and flood direction. The current was required to build up on its own accord from essentially zero velocity in the ocean, reach a maximum value in the inlet throat and decay to essentially zero velocity in the bay region, for the flood condition. The ebb condition was similar except the current opposed the direction of the wave motion. For a variety of steady-state flow conditions through the facility, a range of wave trains with initial characteristics representative of those found in nature were superimposed. Measurements of velocity, wave height, and wave length were determined at selected points along the axis of the facility. Pertinent photographic documentation aided in understanding the phenomena of wave energy losses occurring in the ocean region. ...
Hales, Zelton Lyndell (1974). The effects of a steady nonuniform current on the characteristics of surface gravity waves. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -171042.