Understanding the mechanisms of solute transfer across the sediment-water interface plays a crucial role in water quality prediction and management. In this study, different arranged particles are used to form typical rough and permeable beds. Large Eddy Simulation (LES) is used to model the solute transfer from the overlying water to sediment beds. Three rough wall turbulence regimes, i.e., smooth, transitional and rough regime, are separately considered and the effects of bed roughness on solute transfer are quantitatively analyzed. Results show that the classic laws related to Schmidt numbers can well reflect the solute transfer under the smooth regime with small roughness Reynolds numbers. Under the transitional regime, the solute transfer coefficient (K_L⁺) is enhanced and the effect of Schmidt number is weakened by increasing roughness Reynolds number. Under the rough regime, the solute transfer is suppressed by the transition layer (Brinkman layer) and controlled by the bed permeability. Moreover, it is found that water depth, friction velocity and bed permeability can be used to estimate the solute transfer velocity (K_L) under the completely rough regime.

中文翻译：

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粗糙度和渗透率对沉积物水界面溶质迁移的影响

了解溶质在沉积物-水界面的转移机理在水质预测和管理中起着至关重要的作用。在这项研究中，使用不同排列的颗粒来形成典型的粗糙且可渗透的床层。大涡模拟（LES）用于模拟溶质从上覆水到沉积床的转移。分别考虑了三种粗糙的壁湍流状态，即光滑，过渡和粗糙状态，并定量分析了床粗糙度对溶质迁移的影响。结果表明，与施密特数有关的经典定律可以很好地反映出在具有较小粗糙度雷诺数的光滑状态下的溶质转移。在过渡状态下，溶质转移系数（K _L ⁺）通过增加粗糙度雷诺数来增强），并削弱施密特数的影响。在粗糙状态下，溶质的转移受到过渡层（布林克曼层）的抑制，并受到床层渗透率的控制。此外，发现在完全粗糙的条件下，水深，摩擦速度和床渗透率可用于估算溶质的传输速度（K _L）。