Multilayer Numerical Modeling of Flows through Vegetation Using a MixingLength Turbulence Model

Barrios-Piña Hector, Ramírez-León Hermilo, Rodríguez-Cuevas Clemente, Couder-Castañeda Carlos
Water, Number 7, Vol. 6, pp.2084-2103, 2014.


This work focuses on the effects of vegetation on a fluid flow pattern. In this numerical research, we verify the applicability of a simpler turbulence model than the commonly used kepsilon model to predict the mean flow through vegetation. The novel characteristic of this turbulence model is that the horizontal mixinglength is explicitly calculated and coupled with a multilayer approach for the vertical mixinglength, within a general threedimensional eddyviscosity formulation. This mixinglength turbulence model has been validated in previous works for different kinds of nonvegetated flows. The hydrodynamic numerical model used for simulations is based on the Reynoldsaveraged NavierStokes equations for shallow water flows, where a vegetation shear stress term is considered to reproduce the effects of drag forces on flow. A secondorder approximation is used for spatial discretization and a semiimplicit LagrangianEulerian scheme is used for time discretization. In order to validate the numerical results, we compare them against experimental data reported in the literature. The comparisons are carried out for two cases of study: submerged vegetation and submerged and emergent vegetation, both within an open channel flow.