This paper presents a vegetated flow and sediment transport model for investigating flow–vegetation–sediment interactions. Vegetation-induced turbulence is simulated by a $k-\epsilon$ turbulence closure, in which shear and stem-scale wake turbulent kinetic energies are solved separately. The model simulates both unidirectional and oscillatory flows as well as turbulence structures reasonably well with the model skill greater than 0.8 and the coefficient of determination greater than 0.95, and better agreements between simulations and measurements are observed in cases with large stem Reynolds number. To account for sediment suspension induced by wake turbulence within the canopy, a modified Shields parameter based on turbulence intensity is introduced. Compared to the traditional Shields number model in which sediment suspension is related to mean flow, the proposed model can more reasonably simulate sediment suspension in a dense vegetation canopy with the model skill greater than 0.8 and the coefficient of determination greater than 0.75, where mean flow is weak and stem-scale wake turbulence is dominant. The model uncertainties are evaluated by conducting sensitivity tests on the new coefficients introduced in the turbulence and sediment models. The influence of vegetation density on sediment suspension is also investigated. It is found that suspended sediment concentration is generally higher with higher vegetation density within the canopy, and lower with increasing vegetation density above the canopy.

本文提出了一种植被流与泥沙输移模型，用于研究流—植被—泥沙相互作用。植被引起的湍流由$ķ-\epsilon$湍流闭合，其中剪切力和茎尺度尾流的湍动能被分别求解。模型技巧大于0.8且确定系数大于0.95时，该模型可以很好地模拟单向流动和振荡流动以及湍流结构，并且在大雷诺数情况下，可以更好地模拟和测量结果。为了解决顶篷内湍流引起的泥沙悬浮，引入了基于湍流强度的修改后的Shields参数。与传统的Shields数模型（其中泥沙悬浮与平均流量相关）相比，该模型可以更合理地模拟模型技能大于0的茂密植被冠层中的泥沙悬浮。8和确定系数大于0.75，其中平均流量较弱，而茎级尾流则占主导地位。通过对湍流和沉积物模型中引入的新系数进行敏感性测试来评估模型的不确定性。还研究了植被密度对沉积物悬浮的影响。研究发现，随着冠层内较高的植被密度，悬浮的泥沙浓度通常较高，而随着冠层上方的植被密度增加，悬浮物的浓度较低。