The hydraulic investigation of inflatable weirs

Abstract

In this research, the models of Inflatable weirs with internal pressures of 0.5 and 1.4 at three heights of 0.15, 0.2 and 0.25 m were constructed. The deflectors were used in two geometric sections, including rectangular and triangular shapes, and they were installed at angles of 30, 45, and 60 degrees downstream of the weir body. The results showed that the value of the Cd changes between 0.28 and 0.35 while the range of the ratio of the upstream flow head on the crest to the radius of the downstream side of the inflatable weir varies between 0.2 and 1.5. The flow by crossing over the inflatable weir and colliding with the surface of the downstream stilling basin loses its energy by about 10–85%. The relative horizontal distance of the projectile-jet from the crest varies between 1.6 and 2.8. The effect of the deflector on the Cd is negligible due to being located in the supercritical part of the weir. Examination of the obtained results declared that the deflector has a considerable effect on energy dissipation. HIGHLIGHTS The hydraulic properties of the Inflatable weir, including discharge coefficient (Cd), the flow energy dissipation ratio (EDR), and the profile of the outlet jet of the deflector were investigated.; The stage-discharge relation (rating curve) of inflatable weirs was provided.; The effects of defector and its installation angle on the properties of outlet jet and energy dissipation have been investigated.;

Keywords

• deflector
• discharge coefficient
• energy dissipation
• flow measurement
• inflatable weir