scholarly journals Dam-Break Flows: Comparison between Flow-3D, MIKE 3 FM, and Analytical Solutions with Experimental Data

2018 ◽  
Vol 8 (12) ◽  
pp. 2456 ◽  
Author(s):  
Hui Hu ◽  
Jianfeng Zhang ◽  
Tao Li

The objective of this study was to evaluate the applicability of a flow model with different numbers of spatial dimensions in a hydraulic features solution, with parameters such a free surface profile, water depth variations, and averaged velocity evolution in a dam-break under dry and wet bed conditions with different tailwater depths. Two similar three-dimensional (3D) hydrodynamic models (Flow-3D and MIKE 3 FM) were studied in a dam-break simulation by performing a comparison with published experimental data and the one-dimensional (1D) analytical solution. The results indicate that the Flow-3D model better captures the free surface profile of wavefronts for dry and wet beds than other methods. The MIKE 3 FM model also replicated the free surface profiles well, but it underestimated them during the initial stage under wet-bed conditions. However, it provided a better approach to the measurements over time. Measured and simulated water depth variations and velocity variations demonstrate that both of the 3D models predict the dam-break flow with a reasonable estimation and a root mean square error (RMSE) lower than 0.04, while the MIKE 3 FM had a small memory footprint and the computational time of this model was 24 times faster than that of the Flow-3D. Therefore, the MIKE 3 FM model is recommended for computations involving real-life dam-break problems in large domains, leaving the Flow-3D model for fine calculations in which knowledge of the 3D flow structure is required. The 1D analytical solution was only effective for the dam-break wave propagations along the initially dry bed, and its applicability was fairly limited.

1999 ◽  
Vol 36 (4) ◽  
pp. 651-659 ◽  
Author(s):  
Mats Billstein ◽  
Urban Svensson ◽  
Nils Johansson

The focus of this paper is on the development and validation of a numerical model of flow through simplified embankment dams with fractures. Two laboratory experiments were conducted to provide data for validation of the numerical model, one dealing with steady flow in a Hele-Shaw cell and one with steady flow through a bed of packed glass beads. A horizontal fracture, extending from the upstream boundary to a point within the embankment, was used in both experiments, and it was shown to have a significant influence on the discharge, pressure distribution, height of the seepage face, and free surface profile. Comparisons between numerically determined and experimentally measured results were carried out with respect to the discharge, pressure distribution, height of the seepage face, and free surface profile. In the experiments it is shown that a fracture increases the discharge and that the discharge increases more when a fracture is located far away from the free surface profile than when it is located close to the free surface profile. The height of the seepage face above the tailwater is strongly dependent upon the length of the fracture. The influence on the free surface profile is greater when a fracture is close to the free surface profile than when it is far away from the free surface profile. These effects are also found in the numerical simulations. It is thus concluded that the agreement is generally satisfactory between the experimental and numerical results.Key words: numerical model, embankment dam, fracture, experimental data, discharge.


Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1758
Author(s):  
Juan Macián-Pérez ◽  
Francisco Vallés-Morán ◽  
Santiago Sánchez-Gómez ◽  
Marco De-Rossi-Estrada ◽  
Rafael García-Bartual

The study of the hydraulic jump developed in stilling basins is complex to a high degree due to the intense velocity and pressure fluctuations and the significant air entrainment. It is this complexity, bound to the practical interest in stilling basins for energy dissipation purposes, which brings the importance of physical modeling into the spotlight. However, despite the importance of stilling basins in engineering, bibliographic studies have traditionally focused on the classical hydraulic jump. Therefore, the objective of this research was to study the characteristics of the hydraulic jump in a typified USBR II stilling basin, through a physical model. The free surface profile and the velocity distribution of the hydraulic jump developed within this structure were analyzed in the model. To this end, an experimental campaign was carried out, assessing the performance of both, innovative techniques such as the time-of-flight camera and traditional instrumentation like the Pitot tube. The results showed a satisfactory representation of the free surface profile and the velocity distribution, despite some discussed limitations. Furthermore, the instrumentation employed revealed the important influence of the energy dissipation devices on the flow properties. In particular, relevant differences were found for the hydraulic jump shape and the maximum velocity positions within the measured vertical profiles, when compared to classical hydraulic jumps.


2010 ◽  
Vol 57 (11-12) ◽  
pp. 1059-1065 ◽  
Author(s):  
C.E. Blenkinsopp ◽  
M.A. Mole ◽  
I.L. Turner ◽  
W.L. Peirson

1993 ◽  
Vol 20 (3) ◽  
pp. 536-539 ◽  
Author(s):  
Willi H. Hager

Based on a large number of experiments, a simple formula is developed for the time-averaged free surface profile of a classical hydraulic jump. This novel approach is based on the length of the roller. The resulting surface profile fits the data well for usual inflow Froude numbers in the range of 2 to 10. Key words: backwater, channel flow, hydraulics, open channel, surface profile.


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