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The main objective of the paper is to use the detailed measurements of wave and current motions in the Large-scale Sediment Transport Facility (LSTF) at the Coastal and Hydraulics Laboratory (CHL), ERDC, Vicksburg, to compare with model simulations and particularly to investigate the accuracy of two wave models used for driving nearshore circulation computations. The major questions asked are how accurate are the models? And how do the inevitable inaccuracies in the prediction of the wave quantities influence the current predictions? The LSTF is one of a few large-scale facilities around the world designed to accurately reproduce the 2-D horizontal flow and sediment conditions in the nearshore region of a littoral coast. The measurements include all relevant wave data such as wave heights, setup variations, 2-D current distributions across the basin, and a detailed cross-shore array of measurements of the 3-D current structures. The two wave model formulations used for the comparisons are versions of the kinematic wave model, one using sinusoidal the other using non-sinusoidal wave shapes both before and after wave breaking, as wave drivers in the quasi-3-D model SHORECIRC (SC). The comparisons with the measurements are aimed at providing an overall picture of both the flow conditions and the model performance. The discussions provide insight into the mechanisms behind the complex nearshore dynamics and demonstrate the strengths and weaknesses of the two methods in a comprehensive comparison of available wave and current data. The comparisons also reveal that an essential requirement for a wave driver is its capability to represent the phase motion of the wave and its capability to correctly predict the phase speed of waves. |
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