Partially-distributed submerged canopy flows (PSCFs), characterized by the presence of multiple mixing interfaces, are a common feature in riverine and wetland systems. These flows are subject to shear-induced instabilities at the mixing interfaces, which tend to generate multi-dimensional large-scale vortices (LSVs). Yan et al. (2022a) have highlighted the presence of both expected canopy shear layers and unexpected three-dimensional hydrodynamic features in PSCFs. In this paper, we focus on quantitatively analyzing the contribution of different transport mechanisms to individual momentum fluxes, and on identifying the underlying similarity in these fluxes. The results indicate that advection momentum fluxes, generated by secondary circulations (SCs), are equally important as LSVs-driven diffusion momentum fluxes near the mixing interfaces. LSVs transfer momentum from the outer free waters through turbulent diffusion to the canopy interior, while momentum is consumed by the SCs in the area across the interfaces. Consequently, the coexistence of SCs-driven advection and LSVs-driven diffusion leads to particular hydrodynamic features such as near-bed velocity deflection in the junction, outward shift of horizontal mixing layer, significant transverse variation of energy slope and so on. In addition, the observations confirm that the value of the momentum fluxes high depends on canopy geometric and hydraulic factors, enabling the achievement of the dependency of several momentum fluxes on canopy geometric and hydraulic metrics with the self-similarity analysis. This research offers new insights into the essential physical interpretation of three-dimensional flow behavior subject to multiple mixing interfaces in PSCFs.

部分分布的冠层淹没流 (PSCF) 以存在多个混合界面为特征，是河流和湿地系统的共同特征。这些流动在混合界面处受到剪切引起的不稳定性的影响，这往往会产生多维大规模涡流 (LSV)。严等。(2022a)强调了 PSCF 中预期的冠层剪切层和意想不到的三维水动力特征的存在。在本文中，我们专注于定量分析不同传输机制对单个动量通量的贡献，并确定这些通量中潜在的相似性。结果表明，由二次环流 (SC) 产生的平流动量通量与混合界面附近的 LSV 驱动的扩散动量通量同样重要。LSVs 通过湍流扩散将动量从外部自由水域转移到冠层内部，而动量被跨界面区域的 SCs 消耗。最后，SCs驱动的平流和LSVs驱动的扩散的共存导致了特定的流体动力学特征，如交界处的近床速度偏转、水平混合层向外移动、能量斜率的显着横向变化等。此外，观测证实动量通量的值高度依赖于冠层几何和水力因素，从而能够通过自相似分析实现多个动量通量对冠层几何和水力指标的依赖性。这项研究为 PSCF 中受多个混合界面影响的三维流动行为的基本物理解释提供了新的见解。观察证实动量通量的值高取决于冠层几何和水力因素，从而能够通过自相似性分析实现几个动量通量对冠层几何和水力指标的依赖性。这项研究为 PSCF 中受多个混合界面影响的三维流动行为的基本物理解释提供了新的见解。观察证实动量通量的值高取决于冠层几何和水力因素，从而能够通过自相似性分析实现几个动量通量对冠层几何和水力指标的依赖性。这项研究为 PSCF 中受多个混合界面影响的三维流动行为的基本物理解释提供了新的见解。