Author(s): Luna B. J. César; Salas V. Cristian; Gracia S. Jesús; Ortiz M. Victor
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Keywords: Spilway; Turbulent kinetic energy; FLOW 3D
Abstract: This present work aims to characterize a turbulent flow that occurs in a trapezoidal section stilling basin, which belongs to the" Tunel Emisor Oriente" (TEO) project, concerning to the deep drainage system from the Mexico City, with a design caudal of 240 m³/s. The physical model was constructed with a 1: 30 scale, where it was found that its functionality during the design condition set up would be committed due to overflow. Through modification of the geometrical characteristics of the chute, at the entrance section of the tank, we sought to obtain a higher dissipation of turbulent kinetic energy (TKE) and decrease the levels variations of water depth. To evaluate these new geometries and their effects, three different physical assays were performed on the model, these being: the test on the smooth spillway (smooth spillway) ,the second one was carried out by increasing its roughness using steps in the chute (stepped spillway) and the third and last one exchanging the steps with two rows of baffles with the form of teeth (spillway with deflectors) .The physical model was instrumented with acoustic Doppler Velocimeter (ADV) and a digital water level gage. With which the instantaneous speed and level fluctuations was measured, also with this a grid was drawn to calculate the velocity, turbulent kinetic energy (TKE) and its dissipation. In addition, a CFD modeling was performed using the computational software FLOW 3D with same dimensions as the physical model to compare the modification of turbulence. From the comparison of the physical and numerical models some similarity in the calculated indexes is observed, however it is noted that the numerical model underestimates values, so it is necessary some modification in its parameters in order to obtain better results, closer to reality.
Year: 2015