Outflow calibration for vertically distorted models of thermally stratified reservoirs

This paper describes a calibration approach to relate outflow temperature to rate of outflow release from a large, vertically distorted hydraulic model designed to simulate selective withdrawal of colder water from a thermally stratified reservoir. The calibration relationship resulting from the approach is of use for other vertically distorted hydraulic models of stratified flows, especially when such models involve markedly three-dimensional flows that have large-scale turbulence structures. The approach entails accounting, at least approximately, for the influences of flow vorticity on mixing, and it leads to a new similitude consideration and relatively simple relationship for estimating an outflow calibration factor. The calibration approach was supported by tests conducted with undistorted and vertically distorted scale-model replications of a reservoir intake structure and its surrounding bathymetry. This paper also describes the modifications that would enable the intake to release colder water from the reservoir during summer months.