Reynolds stress modeling of 3-D turbulent flow in a partially vegetated open channel

Vegetation growing inside rivers influences the flow resistance, the discharge capacity of the channel and has significant effect on erosion and sedimentation processes. Hence, knowledge of the complex velocity field and turbulence characteristics is of fundamental importance. In the present study three dimensional computations of the Volume-Averaged Reynolds-Averaged Navier-Stokes (VARANS) equations, in conjunction with a Reynolds Stress turbulence model based on a vegetation dynamics approach, are performed in order to simulate the effect of vegetation on the channel flow. Numerical results (streamwise velocity, shear stresses, among others) are compared satisfactorily with available experimental data. Moreover numerical results are compared with analytical results, based on the wellknown SKM method which is used in practical applications for predicting the depth-averaged velocity, shear stress and the carrying capacity of such channels.