Energy loses due to vegetation in open channel flow

Unsubmerged rigid vegetation has a significant impact on flow resistance in open channel. In this experimental study, measurements were conducted to explore the impacts of different diameter and vegetation community composition within the flow domain on velocity and flow depth. All the experiments were performed in a rectangular open channel measuring 18m in length, 0.70 m in width and 0.5 m in depth. In experiments, carried out two pipes having different diameters were used to represent the vegetation. The discharge and water level were measured and used to calculate the roughness coefficients (Manning n, Darcy-Weisbach f and Chezy C). Manning (n), Darcy-Weisbach (f) and Chezy (C) coefficients of roughness, Froude number (Fr) and Reynolds numbers (Re) were calculated. The results indicate that the flow resistance varies with vegetation concentration, vegetation configuration, vegetation diameter, channel slope, Reynolds Number, average velocity and vertical cross sectional blockage area. Additionally, success of predicting the experimental data which suggested equations was determined over ninety percent. Keywords: Open channel flows, flow resistance, hydraulic resistance, roughness