English to Serbian Tech/Engineering Environment & Ecology

This laboratory study describes the spatial pattern of deposition observed in a patch of vegetation located at the wall of a channel. There are two sources of sediment flux to the patch: the advection of particles across the upstream leading edge and the lateral dispersion of particles from the adjacent open channel. The relative contribution of these two supplies determines the spatial pattern of net deposition in the patch. We define the advection length scale within the patch as the longitudinal distance over which advection contributes a significant sediment source. At distances from the leading edge that are within the advection length scale, net deposition in the patch is laterally uniform, reflecting the laterally uniform mean flow delivering the particles. At distances farther than the advection length scale from the leading edge, the net deposition is highest near the flow-parallel edge and decreases into the patch, which is the signature of dispersive transport from the patch edge. Two processes contribute to the lateral dispersion, both of which are associated with the shear-layer vortices formed at the flow-parallel interface between the patch and the channel.


The difference between U1 and U2 creates a shear layer at the interface between the parallel regions of emergent vegetation and open channel that in turn generates large coherent vortices via the Kelvin-Helmholtz instability, as also seen in free and shallow shear layers .