الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 163 |  |  |
| | | from | 163 | | |
Abstract
The egyptian civilization based on the existence of river nile, therefore it should be mastered and controlled to make the best use of it. One of the most common controlling hydraulic structures is the regulators across the river.The present study aims to define the optimum position of a set of groins to minimize the erosion at 450m from the bank facing the diversion channel at new naga hammadi barrage.The barrage is located at a distance of 365.2 km downstream of old aswan dam. Different techniques were used to simulate the flow pattern.Physical work was caried out to investigate the ability of groins with a length of 0.05 from channel width and intermsdiate spacing of 3l were implemented to cover the attacked region.minimum, average, and maximum flow conditions were tested.3 runs tested the case of no groins, 3 tested the discharge at different cross sections. the critical state was for maximum flow condition, while the critical zone is located between 30-50 m from right bank. After grion installation, the maximum velocity increased under fixed discharge and located away from the opposite bank to diversion channel. the simulation is focused on the study of velocity in the longitudinal and transverse directions. in addition, the working length of each group, the fluctuation in water level, and the geometry of scour holes were also investigated.Three effective parameters were examined. The first was is the contraction ratio where 0.05. 0.10, 0.15 and 0.20 were tested. the second is the groin orientation angles; where 3 orientation angles were tested to define three types of groin. Angle of 60% degrees define attracting points, angle 90 degree define the straight groins. Angle of 120 degree define the repelling type groins.