Author(s): Sean Mulligan; Leo Creedon; John Casserly; Richard Sherlock

Linked Author(s):

Keywords: Air–water interface interactions; hydraulic structure design and management; particle tracking velocimetry (PTV); rotating and swirling flows; sewer hydraulics; vortex dynamics

Abstract: A study of the tangential velocity field in a strong free-surface vortex is presented. Experiments were conducted on an open channel scroll type vortex chamber by investigating the tangential velocity for three approach flow conditions. The tangential velocity and circulation fields were ascertained at various sub-surface depths using particle tracking techniques. The results revealed that the experimental tangential velocity distribution is dependent on the initial circulation but is largely independent of the vertical axis. The theoretical tangential velocity profile was found to diverge from the experimental data in the near-field close to the core. It was concluded that the tangential velocity field in this region is strongly dependent on the axial flow conditions. Consequently, an alternative tangential velocity model was developed which models the near-field axial flow effects using the inverse circulation number and an empirical coefficient. Application of a nonlinear least squares multiple regression analysis identified values for the empirical coefficient to obtain a good solution.

DOI: https://doi.org/10.1080/00221686.2018.1499050

Year: 2019