الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The Ministry of Water Resources and Irrigation (MWRI), has constructed various hydraulic structures and facilities along the Nile River to control the release of water in according to planned water demand. Barrages have been built on the Nile River to regulate the water distribution and control the water flow to maximize profitability and minimize the water losses. Examples of these barrages are Esna, and Naga Hammadi Barrages. To maintain the efficiency of the water distribution along the river the MWRI is replacing the old barrages in which their life time is over by new ones. The Esna and Naga Hammadi Barrages were replaced by new ones, which are New Esna and New Naga Hammadi Barrages, respectively. The design and layout of these barrages were tested in a physical model. During testing the New Esna Barrage design and its hydraulic performance on a physical model, it was observed that the scour occurred immediately downstream the stilling basin and exceeded the expected values. This observation has been confirmed during the monitoring of the structure after construction. The same findings were also observed during the design and model testing of New Naga Hammadi Barrage. In both cases significant design modifications have been introduced using trial and error based on expert’s opinion. Therefore, there is a need to develop and improve some design criteria for stilling basins of barrages to be used in future applications and to be suitable for the Nile River conditions.
Different shapes of stilling basins were tested in order to investigate the performance of stilling basins effect on submerged hydraulic jump. (i.e. hydraulic jump length, energy dissipation, velocity distribution, the near bed velocity along the stilling basin and the stability of bed protection downstream the apron). The proposed designs were classified into four groups and each group consisted of two to three designs. The first group consisted of two designs both has sharp end step with model scale height 7.1cm without baffle blocks and with 2 rows of rounded baffle blocks (4 cm diameter). The second group consisted of two designs both designs have end step with height 7.1cm with an additional step (2.38cm high) the first and second design doesn’t has baffle blocks and has 2 rows of rounded blocks with 4cm diameter, respectively. The third group consisted of two designs both have curved end step with radius 1cm and 1.7cm, respectively at which the two designs doesn’t have blocks. The fourth group consisted of three designs and all three designs are with 1cm radius of curved end step
2
(7.1cm high). The first and second design in this group have 2 rows of baffle blocks with height 4.2 cm and 8cm respectively and the third design has a DROP in the slab downstream the curved end step and seven rows of baffle blocks with (7.1cm high)which was installed in this drop.
The experimental work was carried out at the Hydraulics Research Institute, Delta Barrage, Egypt. The flume is 1.0 m wide, 26.0 m long and 1.20 m deep. The side walls along the entire length of the flume are made of glass with steel-frames to allow visual observation of the flow patterns and stability of bed protection. The total number of designs was 9. For each design several runs were performed using 12 different flow conditions.
The study indicated that the design with additional step and rounded blocks and the design with 7 rows of blocks with curved end step had the lowest velocity near the bed. The design with 7 rows of blocks is the most safe design for the stability of bed protection.