Escoamentos do tipo quedas sucessivas sem formação de ressalto hidráulico em canais com o fundo em degraus: simulação e metodologia para o pré-dimensionamento

Abstract

The stepped chutes are important hydraulic structures used as stepped spillways, drainage systems, for fish passage, among other uses. Knowing the characteristics of possible flows in such structures is essential for design. In this work has been studied numerically of the nappe flow without hydraulic jump in chutes with different slopes were performed using the inhohomogeneous multiphase model and the k-ɛ turbulence model, with the purpose of calculating the flow height and presenting methodologies for pre-dimensioning. From the results obtained in the seven numerical simulations carried out with s/l between 0,0594 e 0,80, where s is height and l is the length of the steps, flow profiles and heights, and velocity fields along the stepped chutes were analyzed. Flow depths along the stepped chutes decreasing from the critical level, tending to the quasi-uniform flow regime. Based on this distribution, it was propose a simplified model for the calculation of flow depths and dissipated energy along the stepped chutes. A simplified non-dimensional formulation was also developed for the calculation length and apron elevation of the stilling basin by hydraulic jump. The comparisons made between the numerical solutions and the experimental data indicated that there was adherence between the methodologies. Likewise, the proposed formulations, when compared to the experimental data, showed adherence with deviations less than 7% for most of the data referring to the dissipated energy. Considering the methodology for the pre-dimensioning of stilling basin, the deviations were even smaller.