Flow patterns in an open channel confluence with a small ratio of main channel to tributary discharge

In this paper, time-averaged flow patterns in a 90° open channel confluence with concordant and non-movable bed are studied, for the case of a tributary discharge largely exceeding the main channel discharge. By means of LSSPIV and profiling ADV, velocity data are gathered in laboratory experiments. A moderate and a small ratio of upstream main channel discharge to downstream channel discharge are studied. Intercomparison of the experimental results shows some distinct changes in the flow features.