In this paper, we show that Stokes drift may be significantly affected when an incident intermediate or shallow water surface wave travels over a corrugated sea floor. The underlying mechanism is Bragg resonance: reflected waves generated via nonlinear resonant interactions between an incident wave and a rippled bottom. We theoretically explain the fundamental effect of two counterpropagating Stokes waves on Stokes drift and then perform numerical simulations of Bragg resonance using the high-order spectral method. A monochromatic incident wave on interaction with a patch of bottom ripple yields a complex interference between the incident and reflected waves. When the velocity induced by the reflected waves exceeds that of the incident, particle trajectories reverse, leading to a backward drift. Lagrangian and Lagrangian-mean trajectories reveal that surface particles near the up-wave side of the patch are either trapped or reflected, implying that the rippled patch acts as a non-surface-invasive particle trap or reflector. On increasing the length and amplitude of the rippled patch, reflection, and thus the effectiveness of the patch, increases. The inclusion of realistic constant current shows noticeable differences between Lagrangian-mean trajectories with and without the rippled patch. Theoretical analysis reveals additional terms in the Stokes drift arising from the particular solution due to mean-current–bottom-ripple interactions, irrespective of whether Bragg resonance condition is met. Our analyses may be useful for designing artificial, corrugated sea-floor patches for mitigating microplastics and other forms of ocean pollution. We also expect that sea-floor corrugations, especially in the near-shore region, may significantly affect oceanic tracer transport.

中文翻译：

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修正的斯托克斯漂移是由于在有和没有平均电流的情况下，表面波与波纹状海床之间的共振相互作用所致

在本文中，我们表明，当入射的中间或浅水表面波在波纹海底上传播时，斯托克斯漂移可能会受到显着影响。潜在的机制是布拉格共振：通过入射波和波纹底部之间的非线性共振相互作用产生的反射波。我们从理论上解释了两个反向传播的斯托克斯波对斯托克斯漂移的基本影响，然后使用高阶谱方法对布拉格共振进行了数值模拟。与底部波纹斑片相互作用时，单色入射波会在入射波和反射波之间产生复杂的干扰。当反射波感应的速度超过入射速度时，粒子轨迹会反转，从而导致向后漂移。拉格朗日和拉格朗日均值轨迹显示，贴片向上波侧附近的表面粒子被捕获或反射，这表明波纹的贴片充当非表面侵入性粒子陷阱或反射器。随着波纹状补丁的长度和幅度的增加，反射和补丁的有效性增加。包含实际恒定电流表明，在有无纹波斑的情况下，拉格朗日平均轨迹之间存在明显差异。理论分析揭示了由于平均电流-底部-波纹相互作用而导致的特定解在斯托克斯漂移中的附加项，无论是否满足布拉格共振条件。我们的分析对于设计人工，波纹状海底斑块以减轻微塑料和其他形式的海洋污染可能有用。