Numerical Flow Modeling over Semi-Spherical Obstructions in a Series

Toward a numerical modeling of nature-like fishways embedded with stones

Abstract

This paper is devoted to analyze the change in flow properties by changing the longitudinal spacing between submerged semi-spherical obstructions in a series, from the point of view of designing nature-like fishways embedded with stones. A Godunov type numerical model of two dimensional shallow water equations using quadtree grids has been applied to compute the flow over 3D semi-spherical obstructions. The numerical results show that there is a limit to which obstruction spacing can be reduced to create a favorable flow condition for fish ascending. Likewise, the ratio of velocity reduction reduces as the obstructions become closer.