الفهرس | Only 14 pages are availabe for public view |
Abstract The present experimental study was carried out, to examine the effects of the different blocking ratios upstream the coverage on the hydraulic efficiency of open channels. Previous studies were carried out to cope with this problem in different aspects. They considered the variations in the discharge capacity and heading up resulted from presence of the coverage. Few studies were investigated the impact of blockage ratios upstream the coverage on the hydraulic efficiency of open channels (water depth, heading up, velocity and downstream scour parameters). So, it is intended, in this experimental research, the effect of blocking ratios at the inlet of coverage on the hydraulic efficiency of open channels. The main objectives of this study were to determine the effect of cover part of watercourse by two unsuitable cross sections design of coverage on theses watercourse. Also to study the effect of different blocking ratios on the hydraulic characteristics of the watercourse. Also to determine the difference between the performance of both circular-section and box-section. In order to achieve this. A proposed dimension analysis and an experimental works were developed. All experiments were conducted in the Laboratory of Irrigation and Hydraulics at the Channel Maintenance Research Institute (CMRI), affiliated to the National Water Research Center (NWRC). Number of scenarios with different discharges in case of different blocking ratios were tested. The water surface profiles, water velocity profiles and pilot area of scour for each scenario were examined and recorded. Scenarios of different blocking ratios were conducted and the results were analyzed in some details. Based on this analysis, The characteristics effect of box-sec on term of maximum scour length divided on upstream water depth (Ls/yu) was less than circular-sec with average value ≈25%, that mean the best section in designing coverages was Box-section. |