Flow prediction in two stage wide compound channels

Abstract

The paper reports about flow analysis in a wide compound channel. New experiments are conducted in a two stage compound channel having width ratio more than 11 and aspect ratio more than 5 under various over-bank conditions with relative depth varying between 0.08 and 0.43. These experiments are significant due to rarity of flow investigation in wide compound channel as evident from published literature. In the present work, new equations for predicting boundary shear stress distribution for a wide compound channel in terms of non-dimensional geometric and flow variables are developed. The model can be applied to predict the stage–discharge relation of compound channels of higher width ratio i.e. width ratio more than 6. The efficacy of the approach is tested in the experimental compound channel data-sets, data-sets from large channel facility [Flood Channel Facility channel] at Walling ford, UK, and natural compound river channel data having wide floodplains.

Keywords:

• compound channel
• boundary shear
• discharge
• divided channel method
• non-dimensional flow parameters

Acknowledgements

The authors wish to acknowledge thankfully the support received by the second author from DST India, under grant no. SR/S3/MERC/066/2008 for conducting experimental research work. This article belongs to the papers presented at the Hydro-2012 conference held at IIT Bombay on 7–8 December , 2012 that were short-listed by the Editor for publication in this Journal after rereview and revisions where necessary.