A study on flow characteristics with the interactions of green river corridor through experimental and numerical investigation

In nature, the riparian zones of a river are covered with vegetation which includes small plants to large wood tress. In general, these green river corridors influence the turbulent structure of the main channel. The understanding of this turbulence structure is helpful to maintain the health of the river. It makes important to study the vegetation influence on river turbulence. Understanding of natural processes in the river requires accurate modeling of flow hydraulics in a complex channel with vegetated floodplains. In this study, a series of open channel flow experiments were conducted in the Fluvial hydro-ecological laboratory, at IIT Guwahati. Considering the importance of vegetation for the flow phenomena, in this study the hydrodynamic change due to presence of vegetation cover on floodplain is simulated using Flow3D (FLOW-3D HYDRO v1.0 u 1), a computational fluid dynamic model. The model using a finite volume approach and the two equations turbulence model (Renormalization-Group) adequately reproduce the complex flow velocity patterns in the main channel of the river. From the results, the averaged streamwise velocities in the simulated data were approximately 1.5 times of the experimental result. The mean velocity of streamwise velocity is around 7 for experimental condition and for simulated case is 11. However, the apex and cross-over sections in the main channel measured locations show the reasonable results in the view of velocity core region between simulated and experimental contour plots. Due to the effect of floodplain vegetation, the secondary flow circulations were predicted well in the simulation case than experimental one. Present study is mainly focused on interactions between the green corridor and main channel flow and ultimately drives into the ecological processes of a river. This can help in river restoration program to be highlighted.