A STEADY-STATE SIMULATION OF SMALL AMPLITUDE WIND-GENERATED WAVES.

Abstract : The primary purpose of this investigation was to extend and to improve the results of Zagustin, et al., on steady-state, experimental simulation of wind blowing over small amplitude waves. Experiments were performed in a laboratory open-channel flume in which a belt driven at a constant speed and following the shape of the wave reproduced the moving boundary conditions found at an air-water interface. Water was used as a working fluid. Two sets of new experimental results are presented. The first set was a rerun of the Zagustin experiments in which the moving belt formed one wall of the open channel. Emphasis was placed on increasing the scope and accuracy of the previous results. In the second set of experiments, a cover-plate was added to the open flume to minimize the free-surface disturbances. In both sets of experiments, a pitot-static probe was used to obtain velocity and pressure data. The measured velocity profiles in the flow above the wavy surface were used together with Miles' theory to obtain theoretical pressure distributions for the region near the wavy surface. These were compared to the experimental distributions. Within the limitations of the experimental model, the data verified Miles' inviscid mechanism of energy transfer from a shear-flow to pre-existing small amplitude waves. (Author)