A numerical study of the transition in the circular hydraulic jump

We performed axisymmetric (r-z) simulations to clarify the structure formation of the circular hydraulic jump, The transition from a type I to a type II jump, which was induced by changing the depth of the fluid far away from the jet in the laboratory experiment, was investigated numerically. We found that the transition is associated with a rise in pressure beneath the surface immediately after the hydraulic jump, This result shows that the hydrostatic assumption used in most of the theoretical studies may not be appropriate for the formation of a type II jump. (C) 1999 Elsevier Science B.V. All rights reserved.