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Theoretical Model of Suspended Sediment Concentration in a Flow with Submerged Canopy

Author(s): Da Li; Zhonghua Yang; Wenxin Huai

Linked Author(s): Zhonghua Yang, Da Li, Wenxin Huai

Keywords: Canopy flow; Two-layer; Suspended sediment distribution

Abstract: A theoretical model for predicting the vertical distribution of suspended sediment concentration in a flow with submerged canopy is proposed in this study. Based on the previous study, the flow with submerged canopy is divided into two parts, the free water layer and the canopy layer. The longitudinal velocity profiles which are logarithmic in the free water layer and exponential in the canopy layer are adopted and tested, respectively. In deriving suspended sediment concentration distribution formula, it is assumed that the diffusion coefficient is equivalent to the momentum exchange coefficient determined by the gradient of velocity and the Reynolds stress. The predicted profile of suspended sediment concentration moderately agrees with the experimental data. To study the influence of canopy on the distribution of suspended concentration, the predicted profiles are compared with that simulated by the Rouse Formula for the flow without canopy. The compared results indicate that the existence of canopy will make more sediment deposited. Finally, at the same hydrodynamic conditions, the simulated sediment distribution profiles with different canopy density reveal that the variation tendency of the sediment distribution profiles in the free water layer is contrary with that in the canopy layer. And with the canopy density increasing, it will have the less effect on the distribution profile.


Year: 2018

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