Abstract
Laboratory experiments and numerical simulations were conducted to investigate interactions of flow and sediment with vegetation. Four experimental and numerical cases were carried out with three patch densities and without a patch. Vegetation patch was located at middle of a channel. For un-vegetated condition, channel widening with bank erosion occurred, but for vegetated channel, bank erosion took place opposite the patch and sediment was deposited downstream of the patch in both experiments and numerical simulations. In experiments, local scour occurred around the patch and scour depth increased with patch density. However, 2D shallow flow model did not reproduce such phenomena. This was due to three dimensional effects such as reinforcement effects and horseshoe vortex caused by individual stems. Nevertheless, numerical results reasonably agreed with experimental results.
