Profiles and energy of transitional tumbling flow around a large bed element

Abstract

The transition from supercritical to subcritical flow observed in a laboratory flume is characterized in the presence of a single large bed element (LBE). The present description is both qualitative and quantitative. Three types of jets are identified as a result of water striking the LBE. Transitional tumbling flow around the LBE follows one of three possible surface profiles:

1. the backward breaking jet;

2. the stationary nonbreaking jet;

3. the forward shooting jet.

Dimensionless parameters that describe the problem include geometric ratios and the Froude number. Energy dissipation due to the deflected jets is evaluated in terms of the geometry of the LBE and the flow characteristics after the impact of water on the LBE.