Side-Channel Flow: Physical Model Studies

摘要

Hydraulic investigations of three hydraulic model studies on side channels are presented. These include the side channels of the Trangslet Dam, Sweden, the Karahnjukar Dam, Iceland, and the Lyssbach diversion tunnel, Switzerland, of which the former two have a trapezoidal cross section and the latter has a rectangular cross section. The observed flow patterns are described, with particular attention on the single-and two-vortex spiral flow patterns, the formation of a tornado vortex, and air entrainment. The measured streamwise free-surface profiles are compared with one-dimensional computations on the basis of the standard spatially varied flow equation. Although a good agreement results in general, deviations are primarily explained by local perturbations. The measured cross-sectional free-surface profiles indicate an increase in the flow depth along the side walls compared with the computed flow depth at the impact point of lateral inflow. For the side-channel design, safety provisions should therefore be considered. Side channels with geometrical complexities and a high hazard potential should be investigated in detailed hydraulic model tests, whereas the remainder essentially follows computations on the basis of the preceding procedure. (C) 2015 American Society of Civil Engineers.