A two-experiment approach to hydraulic jump scaling

Abstract

A hydraulic jump is a sudden rapid transition from a fast to a slower moving flow that is readily observed in open channels. The phenomenon has been extensively investigated both theoretically and experimentally, and is influenced by turbulence, gravity, wall friction, and fluid viscosity. The behaviour of a jump changes under scaling, which limits experimental investigations performed at scale, making scaled models unrepresentative. This issue is addressed in this paper with the introduction of a new experimental approach involving more than one scaled model. A new theory for scaling has recently appeared in the open literature that systematically removes scale effects by means of alternative similitude rules not available to dimensional analysis. This main focus in this paper is on the rule known as the first-order finite-similitude rule, involving two scaled experiments. The question addressed in the paper is whether it is possible, by means of additional scaled experiments, to capture more accurately hydraulic-jump behaviour. Both theoretical and experimentally-validated results are examined from the literature to support the contention that an additional scaled experiment provides significantly improved outcomes.