Weirs are widely used to control and regulate the flow in open channels. In gabion structures, the flow conditions are more complex due to the complexity of flow through the porous body of a gabion. The present study aims to investigate the water surface profile, the overflow velocity profile, and both the through-flow and overflow ratios. Six physical models of the three downstream slopes (V:H 1:1, 1:2, and 1:3) and two types of rockfill (crushed stone and rounded gravel) were investigated. Results show that for the same discharge, the milder slope model (1:3) shows higher water surface and higher velocity than the steeper slope (1:1) with about 9 and 8% on average respectively. The water surface was 60% higher on the lower steps than on the upper steps at the nappe flow regime. Moreover, the low porosity models show a slightly higher velocity and flow depth than higher porosity models for all sections. Furthermore, increasing the porosity from 0.38 to 0.42 led to about a 27% increment in the through-flow ratio. Finally, four relationships were developed to estimate the through-flow and overflow ratios at the upstream and inner sections of the gabion weir. The suggested relationships can be considered novel relationships.
It is important to determine the limits of flow regimes in the design of stepped weirs because of the hydraulic performance of each regime. The present study investigates the effect of downstream slope and rock fill materials on flow regimes in gabion stepped weirs. Nine physical models of gabion weirs were used in the experiments. The models' downstream slopes ranged from 1:05 to 1:4 V:H. In addition, two types of rockfill materials: crushed stone of 0.42 porosity and rounded gravel of 0.38 porosity were used to study the effect of rockfill materials on flow regimes. The nominal size of the crushed stone was (37.5 mm -13.2 mm) D50 = 23 mm and the nominal size of the rounded gravel was (26.5 mm -13.2 mm) D50 = 16 mm. Each model has been tested with ten runs for discharge per unit width ranging (from 0.006 to 0.105 m 3 /sec. m) to cover all flow conditions and flow regimes. The onset of each flow regime for all physical models has been observed. The experimental data of the gabion stepped weirs have been used to develop equations to estimate the onset of each flow regime. The coefficient of correlation (R) of the developed equations ranged between 0.95 to 0.97. The results indicated on the steeper downstream slope models (1:0.5, 1:0.83), there is interference between the nappe and transition flow regimes. The nappe flow regime has not appeared on all steps at the same
The analysis of the hyperspectral image is an important method used in mineral detection. A map of the Feldspar mineral will produced for the study area, which lies to the west of the holy province of Karbala and limited in image that download from USGS website (type hyperspectral image from EO-1 satellite) , by using Spectral Angle Mapper (SAM) technique in the Erdas software, which is based on calculating the spectral reflection curve of any point on the image and the spectral reflection curve of feldspar mineral that is available in the spectral library of the software. For the purpose of verifying the results of the image analysis, ground truth ( field work ) was used by collecting 12 soil samples and finding the spectral curve for each sample by the spectral analysis device (ASD) and the result show the match between image and ground, where produced Feldspar mineral map.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.