In shallow coastal oceans, turbulent flows driven by surface winds and waves and constrained by a solid bottom disperse particles. This work examines the mechanisms driving horizontal and vertical dispersion of buoyant and sinking particles for times much greater than turbulent integral time scales. Turbulent fields are modeled using a wind‐stress driven large eddy simulation (LES), incorporating wave‐driven Langmuir turbulence, surface breaking wave turbulent kinetic energy inputs, and a solid bottom boundary. A Lagrangian stochastic model is paired to the LES to incorporate Lagrangian particle tracking. Within a subset of intermediate buoyant rise velocities, particles experience synergistic vertical mixing in which breaking waves (BW) inject particles into Langmuir downwelling velocities sufficient to drive deep mixing. Along‐wind dispersion is controlled by vertical shear in mean along‐wind velocities. Wind and bottom friction‐driven vertical shear enhances dispersion of buoyant and sinking particles, while energetic turbulent mixing, such as from BW, dampens shear dispersion. Strongly rising and sinking particles trapped at the ocean surface and bottom, respectively, experience no vertical shear, resulting in low rates of along‐wind dispersion. Crosswind dispersion is shaped by particle advection in wind‐aligned fields of counter‐rotating Langmuir and Couette roll cells. Langmuir cells enhance crosswind dispersion in neutrally to intermediately buoyant particles through enhanced cell hopping. Surface trapping restricts particles to Langmuir convergence regions, strongly inhibiting crosswind dispersion. In shallow coastal systems, particle dispersion depends heavily on particle buoyancy and wave‐dependent turbulent effects.

中文翻译：

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浮力和下沉颗粒在模拟的风和波驱动的湍流沿海海洋中的扩散

在沿海浅海中，由地表风和波浪驱动并受固体底部约束的湍流分散了颗粒。这项工作研究了驱动浮力和沉没粒子在水平和垂直方向上分散的机制，其时间远大于湍流积分时标。湍流场是利用风应力驱动的大涡模拟（LES）建模的，其中包含了波浪驱动的朗缪尔湍流，表面破碎波湍流动能输入和坚实的底部边界。将拉格朗日随机模型与LES配对，以合并拉格朗日粒子跟踪。在中间浮力上升速度的子集中，颗粒经历协同的垂直混合，其中，破碎波（BW）将颗粒注入到足以驱动深度混合的Langmuir下降速度中。沿风的弥散度是由垂直沿平均风速的剪切力控制的。风和底部摩擦驱动的垂直剪切增强了浮力和沉没颗粒的分散，而高能量的湍流混合（例如来自BW的湍流混合）则抑制了剪切分散。分别捕获在海面和海底的强烈上升和下沉的颗粒不会受到垂直剪切，从而导致顺风散布率较低。逆风扩散是通过粒子对流在反向旋转的朗缪尔（Langmuir）和库埃特（Couette）滚动单元的风向场中形成的。朗格缪尔细胞通过增强的细胞跳变作用增强了侧风在中性至中性浮力颗粒中的分散。表面捕获将粒子限制在Langmuir会聚区域，从而强烈抑制了侧风的扩散。在沿海浅层系统中，