STUDY OF THE FLOWTHROUGH NON-SUBMERGED VEGETATION  

作　　者：NEHAL Laounia YAN Zhong-min XIA Ji-hong 

机构地区：[1]College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China

出　　处：《Journal of Hydrodynamics》2005年第4期498-502,共5页水动力学研究与进展B辑（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant No :30490235) .

摘　　要：Vegetation is an important feature of many rivers. Vegetation along rivers produces high resistance to flow and, as a result, has a large impact on water levels in rivers and lakes. The effects of instream-unsubmerged vegetation （such as the reed-similar Kalmus） on flow resistance and velocity distributions is studied in the paper. Artificial vegetation is used in the experimental study to simulate the Acorus Calmus L. As shown in experimental tests the resistance depends strongly on vegetation density and the Manning resistance coefficient varies with the depth of flow. A simplified model based on concepts of drag is developed to evaluate the roughness coefficient （Manning＇s n） for non submerged vegetation. In vegetated channels the overall flow resistance is influenced significantly by the distribution pattern of the vegetated beds. Within vegetation, vertical variation in velocity is different from that in the non vegetated bed, which reflects the variation in vegetation density. Vertical turbulent transport of momentum is negligible as demonstrated by experiments.Vegetation is an important feature of many rivers. Vegetation along rivers produces high resistance to flow and, as a result, has a large impact on water levels in rivers and lakes. The effects of instream-unsubmerged vegetation （such as the reed-similar Kalmus） on flow resistance and velocity distributions is studied in the paper. Artificial vegetation is used in the experimental study to simulate the Acorus Calmus L. As shown in experimental tests the resistance depends strongly on vegetation density and the Manning resistance coefficient varies with the depth of flow. A simplified model based on concepts of drag is developed to evaluate the roughness coefficient （Manning＇s n） for non submerged vegetation. In vegetated channels the overall flow resistance is influenced significantly by the distribution pattern of the vegetated beds. Within vegetation, vertical variation in velocity is different from that in the non vegetated bed, which reflects the variation in vegetation density. Vertical turbulent transport of momentum is negligible as demonstrated by experiments.

关 键 词：open channel flow non-submerged vegeta-tion vegetation density flow resistance velocity distribution 

分 类 号：Q948.2[生物学—植物学]