Three-Dimensional Flow of a Vortex Drop Shaft Spillway with an Elliptical Tangential Inlet

Vortex drop shaft (VDS) spillways are eco-friendly hydraulic structures used for safely releasing flood. However, due to the complexity of three-dimensional rotational flow and lack suitable measuring devices, current experimental work cannot interpret behavior reliably inside VDS spillway, consequently CFD study on a spillway with an elliptical tangential inlet was conducted further discern interior behavior. Hydraulic characteristics such as wall pressure, swirl angle, annular height Froude number tapering section experimentally obtained acceptably agreed numerical prediction. Results indicated that relative dimensionless maximum standing wave falls off nearly linearly increasing number. Nonlinear regression established give estimation minimum air-core rate. The normalized jump depends phenomena pressure slope. Simulated results sufficiently reveal velocity field (resultant velocity, axial radial velocity) obvious regional cross-sectional variations vortex shaft. It is found varies, resembling near-cavity forced near-wall free Analytic calculations were developed correlated well simulated results.