Author(s): Dr. sc. ETH Michael Pfister IAHR Member; Prof. Dr. Willi H. Hager IAHR Member
Keywords: Air concentration; Black water core; Deflector; Free surface aeration; Jet; Trajectory
Abstract: Free jets issued at the end of chutes may be generated rather with deflectors than with flip buckets. The latter jet trajectories were previously investigated, using the standard approach based on the take-off angle. However, few information concerning the air concentration distribution within such jets is presently available. The herein presented study investigates both jet trajectories and the streamwise air concentration development based on 129 hydraulic model tests. The trajectories were normalized using the take-off coordinates and the location of maximum trajectory elevation, to reduce the uncertainties concerning the effective jet take-off angle. The characteristic air concentrations are described as a function of the relative black water jet core length, defined between the take-off section and the location with a minimum of 1% air concentration. An example finally compares the present approach with a former study and illustrates typical air concentration distributions within a deflector-generated jet.