Evaluación de métodos de diseño para conductos con rugosidad artificial mediante experimentación en modelo físico

Abstract

In hydraulic projects for flow transport to free surface, it is often necessary to control the average speed in order not to exceed erosive values. For this purpose, there are empirical methods based on the concept of artificial roughness. The available methods propose to construct, at the bottom of the channel, elements of geometrically regular shapes in order to cause an increase of local resistances, decreasing the speed (Krochin, 1982). The most representative available method presents values of the Chèzy roughness coefficient for roughness types established as double zigzag, cut bars, and continuous bars (Mostkov, 1954). However, aspects related to the effects caused by the variation of flow, bottom slopes and length of the stretch with artificial roughness are still unknown. In the present work, a complementary study is proposed for the method proposed by Mostkov. For the study, experimentation was carried out in a physical model with a reduced scale that was not distorted. The physical model was implemented in a rectangular channel 12 m long and 0.30 m wide, contemplating variations in slope, flow, and configuration of artificial roughness. The study analyzed the performance of three types of artificial roughness in a simplified representation, dynamically and geometrically similar to the phenomenon of flow analyzed, and responds to the factors associated with variation and development of the velocity profile. The study establishes its design, configuration, and behavior for different types of roughness.