Author(s): Yang Fan; Chen Hui-Quan; Guo Jun
Linked Author(s):
Keywords: Diversion angle effect; Lateral intake; Hydraulic behaviour; Open channel
Abstract: The change of the diversion angle at lateral water intakes in open channel has an important influence on the 3-D intake flow structure, and this influence is defined as the “Diversion Angle Effect” in this paper. The main object of this study is to get a better understanding of the difference of intake flow characteristics with different diversion angles. Suggestions are made on the intake layouts based on this study. Flow structures with diversion angles of 90oe45o and 30o are studied. Both laboratory flume experiments and numerical simulations are conducted. Taking the velocity ratio 1/uu f K (mean velocity of the main flow to that of the diversion flow) as a main parameter, some hydraulic features, such as the flow uniformity, diversion width, corner induced eddy, etc. are analyzed. Some important results obtained are as follows: (1) The smaller the diversion angle, the more smooth the flow diverted into the intake channel; the smaller the velocity ratio, the better uniformity the intake flow. (2) When the diversion angle is smallerethe relative diversion width of the main flow is reduced, and the net width of the intake flow is obviously larger. (3) An intake of 90o to the main flow is the least desirable one, because serious separation occurs along the upstream portion of the diversion wall. To get better flow pattern, a diversion angle of within 30o-45o is recommended.
Year: 2009