Hydrodynamic Study of the Flows Caused by Dam Break around Downstream Obstacles

Abstract

Introduction: Studying dam break and the resultant flood routing along with identifying critical areas at the dam downstream are of great importance in safety management of the dam break issues. To reduce the risk of the dam break, an accurate estimation of the effective parameters on the energy dissipation due to the collapse of dams and the flood routing around the downstream natural and artificial obstacles is necessary. Methods: In this research, effects of downstream obstacles (e.g. bridge piers) caused by dam break were investigated on different flood patterns in the flow characteristics. Accordingly, two different geometries of the long and wide reservoirs were considered in the experimental tests and 3D numerical simulations. Results and Conclusion: The results indicated the formation of different flow patterns at downstream of the long and wide reservoirs depends on the reservoir geometry. Due to the alignment of the channel and the reservoir in the long reservoir case, the dominant flow was one-dimensional up to the collision with the pier. Therefore, the one-dimensional solutions, including Ritter analytical solution could be applied in this range. After the flow passes through the pier, due to the formation of the wake vortices, the one-dimensional state was no longer valid. This caused turbulence at the surface of the water, which continued to the end of the channel. In the wide reservoir, from the beginning of the flow entry into the channel until its moment of collision with the pier, as well as passing through it, the flow lost its one-dimensional state. In such a case, the use of 3D models was necessary to achieve the appropriate accuracy.

Investigation of Hydrodynamic Characteristics of Flow Caused by Dam Break around a Downstream Obstacle Considering Different Reservoir Shapes

“…Using three well-known turbulence models standard k   , k   , and k RNG   , the water level changes were compared with laboratory values at G1 and G5 points. By comparing the results obtained from different turbulence models, the RNG (Reynolds Normalized Groups) model was used, which is a highly recommended turbulence model for dam break simulation by numerous references [6,7,16,17].…”

“…Azimi et al [16] and Issakhov et al [1] simulated the effect of different-shaped obstacles located downstream of a channel numerically using the Volume of Fluid (VOF) method. Feizi [17] studied dam break flow hydrodynamics in the presence of a cylindrical obstacle downstream of a channel. He used two different reservoir geometries, wide and long.…”

The Effect of Triangle Slope Variation on Froude Number with Numerical Simulation

“…Previous studies have focused on analyzing flow stability through obstacles and flow speed [3][4][5][6][7]. These studies have identified ways to mitigate the risk of dam failure by accurately estimating the effective parameters concerning energy dissipation, dam collapse, and flooding direction around both natural and artificial obstacles downstream [3].…”

“…Previous studies have focused on analyzing flow stability through obstacles and flow speed [3][4][5][6][7]. These studies have identified ways to mitigate the risk of dam failure by accurately estimating the effective parameters concerning energy dissipation, dam collapse, and flooding direction around both natural and artificial obstacles downstream [3]. Additionally, Yaghoubi et al (2017) demonstrated that an area with negligible speed growth and increasing real concentration upstream around every obstacle becomes larger [5].…”