Influence of T shape baffles arrangement on flow hydraulic characteristics in fishways

Abstract

Hydraulic structures constructed along the rivers cause disturbances in the natural process of aquatic life and the ecosystem of the region. In order to solve this problem, fishway structure is widely used to facilitate the communication path between downstream and upstream of hydraulic structures crossing the river and to eliminate the inability of fish to swim upstream and also to facilitate their movement downstream of dams. The different types of this structure should be designed to absorb the type of migratory fish in the area and to pass them safely and out of the outlet, without injuring the fish or creating unnecessary delays for the adult spawning fish. Therefore, in the present study, in order to determine the optimal configuration of the T shape baffles used in the path, three types of arrangements were numerically simulated using OpenFOAM software and K-ε turbulence model. These three types of arrangements are consecutive, alternate and also reversed. Then, the results of the numerical model were validated by comparing it with the results of the related laboratory model. The findings indicate that the numerical model is in good agreement with the laboratory results. Among the three configurations, taking into account different factors, the reverse location of T-shaped baffles with 68.3% backwater, 86.2% flow at less than 0.5 m/s, 84.1% turbulent kinetic energy values less than 0.02 square meters per square second and also 61% energy dissipation percentage, had the best performance.