This study includes an analytical solution to the wave-current barrier interaction problem and large-scale experiments to validate the theory. The boundary value problem is solved mathematically by characterizing the flow field and barrier motion separately, then coupling the relationships with the appropriate kinematic and dynamic boundary conditions. The flow field …
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This study includes an analytical solution to the wave-current barrier interaction problem and large-scale experiments to validate the theory. The boundary value problem is solved mathematically by characterizing the flow field and barrier motion separately, then coupling the relationships with the appropriate kinematic and dynamic boundary conditions. The flow field satisfies Laplace's equation for irrotational, incompressible flow. A linear wave theory separable velocity potential exists for the flow field fore and aft of the barrier. The velocity potential defines the fluid motions and wave-induced dynamic pressure acting at the barrier. The barrier is modeled as an elastic beam. A modal superposition solution to the equation of barrier motion is expressed as a series product of a free vibration mode shape and a modal participation factor. Coupling of the barrier equation of motion and the flow field is done by specifying the kinematic and dynamic boundary conditions on the barrier. These two conditions allow for the solution of the unknown reflected and transmitted wave amplitudes for the progressive and evanescent modes. A Fortran computer simulation is developed which solves a complex matrix for the unknown reflected and transmitted wave amplitudes from which other quantities of interest are calculated. The computer simulation is used to develop graphs to show how a barrier performs given different structures and wave parameters. Large scale model tests were performed on two different structures at the O.H. Hinsdale Wave Research Laboratory two-dimensional wave channel. Structure and wave response tests were conducted with both monochromatic and random waves. A plywood structure was constructed to approximate a thin elastic beam. An air/water fabric structure was constructed to represent a contemporary inflated membrane barrier. Model geometric and physical characteristics are thoroughly described. Measurements were made to quantify the resulting wave field in the presence of the structure. Experimental results are presented graphically in dimensionless form for each barrier configuration and compared to theoretical predictions.
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