An experimental study on the free surface vertical vortex

Abstract.

An experimental investigation of the three-dimensional configuration of a vertical vortex flow, showing the importance of separating the radial and axial components of the total outflow, is presented. The relative magnitudes of the axial and radial flow components are measured and the depth of the air core is shown to be highly sensitive to the axial flow component. A representation of the flow in the core zone is also presented which may indicate internal boundary conditions that may be of interest to those developing theoretical models.