Dam-break flow experiments over mobile bed: velocity profile. Issue 1 (2nd January 2019)

• Record Type: Journal Article
• Authors: Fent, Ilaria; Zech, Yves; Soares-Frazão, Sandra
• Is Part Of: Journal of hydraulic research. Volume 57:Issue 1(2019)
• Page Start: 131
• Page End: 138
• Publication Date: 2019-01-02
• Subjects: Dam-break flow -- experiments -- mobile bed -- particle image velocimetry (PIV) -- particle-laden flows -- velocity measurements; Hydraulics -- Research -- Periodicals; Hydraulic engineering -- Periodicals; Hydraulic engineering; Electronic journals; Periodicals; 621.2
• DOI: 10.1080/00221686.2018.1444677
• Languages: English
• ISSNs: 0022-1686

Abstract

ABSTRACT: Knowledge of the velocity distribution is key for understanding and modelling any type of flow. For steady flows over fixed beds, theoretical and experimental approaches evidenced a logarithmic law in the inner region, in the vicinity of the bed. For flows over mobile beds or for unsteady flows, the velocity profile progressively adapts to the changing flow conditions. In the present paper, new experiments of dam-break flows over a bed made of coarse sand are presented. Detailed velocity measurements both in the clear water layer and in the moving sediment layer were obtained. The measurements show that a logarithmic velocity profile develops not only in the clear-water layer but also in the upper part of the moving sediment layer, in a similar way to previous observations in steady flow with sheet-flow sediment transport.