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本文按有限元法导出了近岸区由于波动引起的平均水面变化和沿岸流的计算模式。模式中包括非线性对流加速度项,横向混合摩阻项和底摩擦项。为能确定波浪折射场,还用半离散伽辽金(Galarkin)法建立了波浪模式。本模式用一维沿岸流和二维裂流(Rip Currents)的分析解验证了计算精度。此外本模式还应用于予测发生在周期性裂流槽内的游荡性水流(meandering currents)。由于非线性惯性项的影响,使得非加速的沿岸流剖面扩展,引起最大流速数值减小。用一维沿岸流流速分布的分析介比较表明,线性分析介确定的最大流速偏大。数值成果能定量地表明非线性对流加速度项在沿岸流问题中的相对重要性。
Based on the finite element method, the paper deduces the average surface variation and the calculation model of the coastal flow due to the fluctuation in the near-shore area. The model includes nonlinear convective acceleration, lateral hybrid friction and bottom friction term. In order to determine the wave refraction field, the wave mode was also established using the semi-discrete Galakin method. This model verifies the accuracy of the calculation using one-dimensional Rip Currents analytical solutions. In addition, this model is also used to predict the meandering currents that occur in periodic slits. Due to the influence of the nonlinear inertia term, the non-accelerated coastal flow profile is expanded, causing the maximum flow rate to decrease. The analysis of the one-dimensional flow velocity distribution along the shoreline shows that the maximum flow rate determined by the linear analysis method is large. The numerical results can quantitatively show the relative importance of nonlinear convective acceleration in coastal flow problems.