Experimental and Numerical Investigations of Two-Dimensional Dam-Break Flows

• Published in: Journal of hydraulic engineering (New York, N.Y.) Vol. 139; no. 6; pp. 569 - 579
• Main Authors: LaRocque, Lindsey Ann, Imran, Jasim, Chaudhry, M. Hanif
• Format: Journal Article
• Language: English
• Published: Reston, VA American Society of Civil Engineers 01.06.2013
• Subjects: Applied sciences; Buildings. Public works; Computational fluid dynamics; Computer simulation; Dams and subsidiary installations; Exact sciences and technology; Gates; Hydraulic constructions; Large eddy simulation; Mathematical models; Reservoirs; Technical Papers; Turbulent flow; Upstream; Velocity profile; Instantaneous velocity profiles; Rupture; Velocity distribution; Volume of fluid (VOF); Experimental study; Dam failures; Dam; Dam break; Simulation; Test facility; Free surface flow; Numerical simulation; Measurement method; Ultrasonic velocity profiler; Turbulence structure; Ultrasonic method
• ISSN: 0733-9429; 1943-7900
• DOI: 10.1061/(ASCE)HY.1943-7900.0000705

AbstractThis paper presents measurements of velocity profiles obtained from idealized dam-break experiments and results from numerical simulations of these experiments. Dam-break flows were generated in the laboratory by suddenly lifting a gate inside a flume for three different upstream heads with a dry-bed downstream condition. Ultrasonic Doppler velocity profilers were used for recording transient velocity profiles at eight different locations upstream and downstream of the removed gate. These experiments provided data on the spatio-temporal evolution of the flow field in an unsteady flow of relatively short duration. The two-dimensional experiments were simulated using a computational fluid dynamics solver. The following observations are made: (1) turbulence modeling does not affect the velocity profile in the upstream reservoir, but has significant influence on the prediction of downstream velocity; (2) the velocity magnitude at a specific location changes with time, but the shape of the velocity profiles remains similar; (3) an analytical solution for frictionless dam-break flow on a sloping bed and numerical simulation with the large eddy simulation (LES) modeling show satisfactory agreement with measured water surface profile; (4) nondimensionalization of reservoir-side velocity profiles resulting from different reservoir heads and at different locations from a specific head shows excellent collapse and reveals that the shear layer thickness of these profiles is approximately 5% of the initial reservoir head; (5) measurement and simulation with the LES model for turbulence show satisfactory agreement, suggesting that the LES modeling is a viable approach for an accurate prediction of dam-break flows.