Author(s): Menendez Ciro
Linked Author(s):
Keywords: Stepped chute; Energy dissipation; Skimming flow; Configuration; Step cavity
Abstract: The present work is related with the experimental results obtained for a range of flow rates on stepped chutes assembled on a 25-m long laboratory channel and 0. 8-m high and 1. 0-m wide rectangular cross section in order to evaluate the total energy dissipation on the steps for skimming flow regime. For testing, two h/l ratios were taken, chute 1 with h/l = 0. 5 and chute 2 with h/l= 0. 4. Chute 1 was provided with eight and seven steps and chute 2 with ten steps. Besides, in order to compare energy dissipation effectiveness, the step cavities were equipped with vanes or longitudinal ribs with two configurations. Configuration A had 7 vanes in zigzag between two adjacent steps and configuration B had 9 vanes in zigzag in the same way. A third configuration of the step cavities were without vanes and it was called configuration C. For the experiments a discharge range from 70 to 170 l/s was tested and the skimming flow regime was observed. Flow velocity, head pressure and water depth were measured for each discharge as well. As conclusion of the results obtained, it is mentioned that the presence of vanes increased the flow resistance, and the largest rates of energy dissipation -from 63% to 41% - were achieved on configuration A as it was shown for chute 1. For chute 2 with 9 vanes in zigzag or configuration B the difference of flow energy dissipated is low-from 0% to 11% - in comparison with absence of vanes at the step cavity because the chute 2 had more steps than chute 1, therefore for more number of steps on the chute more energy is dissipated
Year: 2007