Aspects aléatoires de l'érosion d'une digue : simulations de la brèche par des algorithmes génétiques

Attempts to forecast the final form of a dam-break suffer from various uncertainty sources such as field data (topography, hydraulic and geotechnical parameters), and modeling assumptions. So the result seems to be at least partially chaotic and difficult to match with the objectives of the dam-safety engineers in which the goal is to model dam-break flow evolution in time. On the other hand, the principle of minimal energy dissipation rate makes it possible to predict the shape towards which the geometry of the breach will evolve to under stationary hydraulic conditions. In this article, one uses energy minimization by a genetic algorithm to integrate at the same time the two concepts of random result and convergence towards an equilibrium state. They are used to simulate the submersion failure of a clay dam, and the results agree reasonably with the field data. This approach makes it possible to obtain as realistic breach shapes as those obtained by actual models, and to introduce a random component in the process of dam-breach formation, which remains, however, guided by a physical principle.Key words: erosion, dam breach, genetic algorithms, sediment transport.

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Study of Dam-break Due to Overtopping of Four Small Dams in the Czech Republic

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun201563030717 ◽

2015 ◽

Vol 63 (3) ◽

pp. 717-729 ◽

Cited By ~ 6

Author(s):

Zakaraya Alhasan ◽

Jan Jandora ◽

Jaromír Říha

Keyword(s):

Czech Republic ◽

Reasonable Agreement ◽

Field Data ◽

Computer Code ◽

Dam Break ◽

Embankment Dam ◽

Dam Breach ◽

The Czech Republic ◽

One Dimensional ◽

Small Dams

Dam-break due to overtopping is one of the most common types of embankment dam failures. During the floods in August 2002 in the Czech Republic, several small dams collapsed due to overtopping. In this paper, an analysis of the dam break process at the Luh, Velký Bělčický, Melín, and Metelský dams breached during the 2002 flood is presented. Comprehensive identification and analysis of the dam shape, properties of dam material and failure scenarios were carried out after the flood event to assemble data for the calibration of a numerical dam break model. A simple one-dimensional mathematical model was proposed for use in dam breach simulation, and a computer code was compiled. The model was calibrated using the field data mentioned above. Comparison of the erodibility parameters gained from the model showed reasonable agreement with the results of other authors.

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EXPERIMENTAL AND THEORETICAL STUDY ON FLOOD BORE PROPAGATION AND MUSHROOM JET GENERATION OF DAM-BREAK FLOW

Visualization of Mechanical Processes An International Online Journal ◽

10.1615/vismechproc.v1.i3.30 ◽

2011 ◽

Vol 1 (3) ◽

Author(s):

H. H. Hwung ◽

Ray Yang ◽

Y. C. Tie ◽

W.Y. Hsu ◽

P. C. Kuo ◽

...

Keyword(s):

Theoretical Study ◽

Dam Break ◽

Dam Break Flow

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Stochastic Uncertainty in a Dam-Break Experiment with Varying Gate Speeds

Journal of Marine Science and Engineering ◽

10.3390/jmse9010067 ◽

2021 ◽

Vol 9 (1) ◽

pp. 67

Author(s):

Hiroshi Takagi ◽

Fumitaka Furukawa

Keyword(s):

High Speed ◽

Pressure Sensors ◽

Dam Break ◽

Maximum Pressure ◽

Vertical Acceleration ◽

Ship Wakes ◽

Dam Break Flow ◽

Statistical Relationships ◽

Flow Propagation ◽

Impulsive Pressure

Uncertainties inherent in gate-opening speeds are rarely studied in dam-break flow experiments due to the laborious experimental procedures required. For the stochastic analysis of these mechanisms, this study involved 290 flow tests performed in a dam-break flume via varying gate speeds between 0.20 and 2.50 m/s; four pressure sensors embedded in the flume bed recorded high-frequency bottom pressures. The obtained data were processed to determine the statistical relationships between gate speed and maximum pressure. The correlations between them were found to be particularly significant at the sensors nearest to the gate (Ch1) and farthest from the gate (Ch4), with a Pearson’s coefficient r of 0.671 and −0.524, respectively. The interquartile range (IQR) suggests that the statistical variability of maximum pressure is the largest at Ch1 and smallest at Ch4. When the gate is opened faster, a higher pressure with greater uncertainty occurs near the gate. However, both the pressure magnitude and the uncertainty decrease as the dam-break flow propagates downstream. The maximum pressure appears within long-period surge-pressure phases; however, instances considered as statistical outliers appear within short and impulsive pressure phases. A few unique phenomena, which could cause significant bottom pressure variability, were also identified through visual analyses using high-speed camera images. For example, an explosive water jet increases the vertical acceleration immediately after the gate is lifted, thereby retarding dam-break flow propagation. Owing to the existence of sidewalls, two edge waves were generated, which behaved similarly to ship wakes, causing a strong horizontal mixture of the water flow.

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A three dimensional dam break flow: Small time behavior

Applied Ocean Research ◽

10.1016/j.apor.2021.102583 ◽

2021 ◽

Vol 110 ◽

pp. 102583

Author(s):

Elona Fetahu ◽

Oguz Yilmaz

Keyword(s):

Three Dimensional ◽

Small Time ◽

Dam Break ◽

Time Behavior ◽

Dam Break Flow

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Investigate Impact Force of Dam-Break Flow against Structures by Both 2D and 3D Numerical Simulations

Water ◽

10.3390/w13030344 ◽

2021 ◽

Vol 13 (3) ◽

pp. 344

Author(s):

Le Thi Thu Hien ◽

Nguyen Van Chien

Keyword(s):

Impact Force ◽

Numerical Models ◽

Splitting Method ◽

Dam Break ◽

Navier Stokes ◽

Dynamic Force ◽

Exact Mass ◽

Initial Water ◽

Dam Break Flow ◽

2D And 3D

The aim of this paper was to investigate the ability of some 2D and 3D numerical models to simulate flood waves in the presence of an isolated building or building array in an inundated area. Firstly, the proposed 2D numerical model was based on the finite-volume method (FVM) to solve 2D shallow-water equations (2D-SWEs) on structured mesh. The flux-difference splitting method (FDS) was utilized to obtain an exact mass balance while the Roe scheme was invoked to approximate Riemann problems. Secondly, the 3D commercially available CFD software package was selected, which contained a Flow 3D model with two turbulent models: Reynolds-averaged Navier-Stokes (RANs) with a renormalized group (RNG) and a large-eddy simulation (LES). The numerical results of an impact force on an obstruction due to a dam-break flow showed that a 3D solution was much better than a 2D one. By comparing the 3D numerical force results of an impact force acting on building arrays with the existence experimental data, the influence of velocity-induced force on a dynamic force was quantified by a function of the Froude number and the water depth of the incident wave. Furthermore, we investigated the effect of the initial water stage and dam-break width on the 3D-computed results of the peak value of force intensity.

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