Abstract
Dam-break flood waves represent a severe threat to people and properties located in downstream regions. Although dam failure has been among the main subjects investigated in academia, little effort has been made toward investigating wave propagation under the influence of tailwater depth. This work presents three-dimensional (3D) numerical simulations of laboratory experiments of dam-breaks with tailwater performed at the Laboratory of Hydraulics of Iskenderun Technical University, Turkey. The dam-break wave was generated by the instantaneous removal of a sluice gate positioned at the center of a transversal wall forming the reservoir. Specifically, in order to understand the influence of tailwater level on wave propagation, three tests were conducted under the conditions of dry and wet downstream bottom with two different tailwater depths, respectively. The present research analyzes the propagation of the positive and negative wave originated by the dam-break, as well as the wave reflection against the channel’s downstream closed boundary. Digital image processing was used to track water surface patterns, and ultrasonic sensors were positioned at five different locations along the channel in order to obtain water stage hydrographs. Laboratory measurements were compared against the numerical results obtained through FLOW-3D commercial software, solving the 3D Reynolds-Averaged Navier–Stokes (RANS) with the k-ε turbulence model for closure, and Shallow Water Equations (SWEs). The comparison achieved a reasonable agreement with both numerical models, although the RANS showed in general, as expected, a better performance.
Highlights
Significant dam-break events produce downstream rapidly-varied unsteady flows, which may determine catastrophic consequences in terms of human losses and damages to properties
The initial reservoir water depth was equal to h0 = 0.15 m in all tests, whereas the tailwater depths hd reservoir water depth was equal to h0 = 0.15 m in all tests, whereas the tailwater depths hd were 0.00 and 0.015 m and 0.030 m, respectively
While unsteady behavior economically straightforwardly the laboratory smallThe oscillations the negative waves from theofflume walls were not findings due showtoareflections significantof difference in the propagation wavefronts between well represented by the
Summary
Significant dam-break events produce downstream rapidly-varied unsteady flows, which may determine catastrophic consequences in terms of human losses and damages to properties. Fraccarollo and Toro [12] carried out experiments of a 3D dam-break model case similar to the one investigated here, but only for dry bed conditions and with a downstream open boundary, measuring water depths and bottom pressures in order to assess the Shallow. Investigations, the 3D propagation of a In partial dam-break wave in an enclosed domain over initially dry andpropagation wet beds with this paper, in contrast to most of the previous investigations, the 3D of two different tailwater levels was experimentally and numerically investigated. A partial dam-break wave in an enclosed domain over initially dry and wet beds withImage two processing was adopted as experimentally a measuring technique, and, ultrasonic sensors different tailwater levels was and numerically investigated. With both methods allowed for the drawing of some interesting conclusions
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