Flow Over Embankment Gabion Weirs in Free Flow Conditions

Abstract

Gabion weirs have been widely used in rivers restoration and diversion water projects because of their hydro-environmental aspects and eco-friendly features. In this study, a series of laboratory tests were performed to investigate the effects of side ramp slope, crest length, and porous media properties on the flow regimes, water-surface profiles, discharge coefficients, and energy dissipation in embankment gabion weirs with upstream and downstream slopes. 24 physical models of solid and gabion weirs with three different upstream/downstream slopes (90°, 45° and 26.5°) were created. For gabion weirs, three different filling materials were tested. To investigate the complexity of flow over the porous-fluid interface and through the porous material, three-dimensional (3D) numerical simulations were developed. The results show that decreasing upstream slopes, from 90º to 26.5º, leads to decreased discharge coefficients. However, in all cases, gabion weirs lead to greater discharge coefficients than those of similar solid weirs. For milder side slopes, discharge ratios passing through all faces of the gabion weirs decreased nonlinearly. Moreover, with increasing the inlet discharge, relative energy dissipation was reduced up to 45% in gabion weirs.

Experimental study on the Hydraulic Performance of Porous Broad-Crested Weirs with Sloping Crests

“…These can be divided into two general categories: 1) most of them investigated the weirs' hydraulic performance (Salmasi and Sattari 2017;Salmasi et al 2021;Biabani et al 2022;Shariq et al 2022), and 2) the second category studied the flow pattern around these structures (Leu et al 2008;Mohammadpour et al 2013;Fathi-et al 2018;Safarzadeh and Mohajeri 2018;Biabani et al 2022). Studies related to hydraulic performance can be divided into two types of weirs: through flow (Michioku et al 2005;Shariq et al 2020) and simultaneous through and overflow.…”