Effect of rigid and emergent vegetation on flow characteristics in a curved channel
In this paper,a 180 degrees U-turn rectangular channel was used to simulate the flow patterns in natural channel bends.The distribution of flow velocity,lateral circulation and the turbulence kinetic energy (TKE) within 4.47％ rigid and emergent model vegetation were studied using the Acoustic Doppler Velocimeter (ADV).The experimental results show that when the flow rate is small,the increase of the water depth within 4.47％ model vegetation is not obvious.On the other hand,as the flow rate becomes larger,the 4.47％ vegetation cause the significant increases in water depth along the channel curve.Due to the vegetation,the velocity profiles along the mean flow direction is no longer subject to logarithmic distribution as the case without vegetation and the lateral circulation patterns disappear as the water flows around the channel bend.In comparison to the case without vegetation,the maximum flow velocity region within vegetation appears earlier in the convex bank but can only move to the central region at the bend exit.The 4.47％ vegetation also enhances the TKE for the bend flow.These findings will improve the understanding of the vegetation role on the flow characteristics of the curved channel and provide guidance for sediment dredging and river ecosystem restoration.
NETL
NSTL
万方数据
维普
