Flat vs. curved rigid-lid LES computations of an open-channel confluence

• Type: Article in International Scientific Journal
• Date: 2019-02-04

Authors

Laurent Schindfessel (Author) Other; Pedro Xavier Ramos (Author) Other; João Pedro Pêgo (Author) FEUP; Tom De Mulder (Author) Other

Journal

Title: Journal of Hydroinformatics

Vol. 21 No. 2

Pages: 318-334

ISSN: 1464-7141

Publisher: IWA PUBLISHING

Indexing

ISI Web of Knowledge - 0 Citations

Scopus - 5 Citations

Scientific classification

CORDIS: Technological sciences > Engineering > Civil engineering > Hydraulic engineering

FOS: Engineering and technology > Civil engineering

Other information

Authenticus ID: P-00Q-BRF

DOI: 10.2166/hydro.2019.109

Abstract (EN): This paper describes the application of four Large Eddy Simulations (LES) to an open-channel confluence flow, making use of a frictionless rigid-lid to treat the free-surface. Three simulations are conducted with a flat rigid-lid, at different elevations. A fourth simulation is carried out with a curved rigid-lid which is a closer approximation to the real free-surface of the flow. The curved rigid-lid is obtained from the time-averaged pressure field on the flat rigid-lid from one of the initial three simulations. The aim is to investigate the limitations of the free-surface treatment by means of a rigid-lid in the simulation of an asymmetric confluence, showing the differences that both approaches produce in terms of mean flow, secondary flow and turbulence. After validation with experimental data, the predictions are used to understand the differences between adopting a flat and a curved rigid-lid onto the confluence hydrodynamics. For the present flow case, although it was characterized by a moderately low downstream Froude number (Fr approximate to 0.37), it was found that an oversimplification of the numerical treatment of the free-surface leads to a decreased accuracy of the predictions of the secondary flow and turbulent kinetic energy.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 17