Hydrodynamic Characterisation of Channel with Submerged Vegetation

This study was conducted to investigate the hydrodynamic characterisation of channel with submerged vegetation. Aquatic plant provides a variety of ecosystem services and plays an important role in the hydrodynamic behavior, the ecological balance and the characteristics of the river. It has an effect on flow resistance and gives great impact on the water level. Laboratory experiment was conducted to investigate the effect of plant densities to flow profile using wood dowel to represent the real plant which was carried out in a hydraulic flume. Solid volume fraction (SVF) is used as vegetation density in this study whereby SVF 3.14% as high vegetation density and SVF 0.79% as low vegetation density. Experimental studies were conducted in uniform flow condition with Reynolds number 554 for lower vegetation density and Reynolds number 375 for higher vegetation density. Results show that the longitudinal velocity magnitude decreases approximately 30% with vegetation density increases from SVF 0.79% to SVF 3.14%. Average velocity, u for this experiment is equal to 4.44 cm/s for lower vegetation density and 3.00 cm/s for higher vegetation resulting calculated Manning’s roughness equal to 0.0937 for higher vegetation density and 0.0633 for lower vegetation density. Furthermore turbulent kinetic energy (TKE) and turbulent intensities are both greater in higher densities vegetated channel compared to the lower densities. Data analysis also calculated the drag coefficient, C_D which is equal to 1.999 for higher vegetation density and 3.680 for lower vegetation density.