Moments-Based Reduced Spectral Wave Modeling of Frequency-and-Directional Spreading Effects on Wave-Induced Longshore Currents

摘要: Often, nearshore radiation stresses are approximated using the monochromatic wave assumption, although this can have significant errors when incident waves finite frequency and/or directional spread. Consequently, resulting wave-driven currents could be predicted erroneously or, fitting to observations, biased model parameters such as bottom friction coefficient may result. We develop and test a moments-based reduced spectral which includes leading order effects of spreading. This solves evolution equations moments, integrations action balance equation multiplied by weighting functions over frequencies directions. An assumption analytical Gaussian distribution for frequency-direction spectrum is made simple five-parameter system that contains information on height, period, direction, bandwidth, bandwidth. Using model, we investigate bandwidth field stresses. The spreading found strong impact stress, with larger in smaller However, has much less impact. breaking based roller concept considered model. After coupling circulation shallow water equations, simulation results compare favorably DUCK94 data longshore but show dependence