Improvement of the Hydraulic Performance of Vertical Slot Fishway Type VI Using Unsubmerged Plates

In this research, the performance of plates installment in the type VI fishway has been numerically investigated using Ansys-Fluent software and the RNG k-ε turbulence model. The effects of the longitudinal plate position from the upstream partition wall (first scheme), the plate angle at the pool inlet (second scheme), and the transversal plate position (third scheme) have been assessed. The results indicate that for different designs in the first, second, and third schemes, the maximum average velocity reductions are 13.40, 19.39, and 11.35%, respectively. These reductions were observed when the plate was positioned near the upstream partition wall, when the plate angle was 45° relative to the side of the pool, and when the plate was situated at the farthest spanwise distance from the right side wall of the pool in the first, second, and third schemes, respectively. Furthermore, the highest reductions in the turbulent kinetic energy for the first, second, and third schemes are 49.61, 51.11, and 41.48%, respectively. The quadruple zones analysis of velocity, vorticity, and turbulence criteria revealed that all schemes create improved flow conditions for fish and enlarge the fish's desired zone. Specifically, the most suitable zones are 48.56, 48.93, and 53.68% of the pool in schemes 1 to 3, larger than the desired zone in the standard base design. Thus, the plate may improve the performance of fishways and can be used in practical problems.