An M.Sc. Degree thesis entitled: "Hydraulic Loading of Impinging Jet Downstream an Overflowing Weir"

Eng. Basem Mohamed Mostafa, Researcher Assistant at the Nile Research Institute (NRI) (affiliate to the National Water Research Center-NWRC), has earned his M.Sc. degree in Irrigation and Hydraulics Department – IHE, The Netherlands, for the thesis entitled "Hydraulic Loading of Impinging Jet Downstream an Overflowing Weir". The objectives of his research is to contribute to a method to assess the stability of existing bed protections, to help the decision-makers defining an intervention plan for replacement or reinforcement of such structures. The approach is to first characterize the hydrodynamic action on the bed (hydraulic loading), after which the resistance capacity of the bed material can be assessed. The scope of this thesis is to contribute to the understanding of the hydrodynamic mechanisms contributing to the loading of the bed protections. This was achieved by analysis of the results of conceptual physical model tests of the impinging jet downstream an overflowing weir. The experiments were performed at Deltares. The data consists of detailed flow velocity measurements and pressure measurements. The velocity measurements were performed by particle image velocimetry (PIV), while the pressure measurements were done using pressure sensors. The measurements are of the uncertainty of about 6%.? Many researchers tried to quantify the hydraulic loading in the formulation of the stability parameters of a non-uniform flow. However, none of the available methods is verified for the case of an overflowing weir. To understand the processes caused by an impinging jet of an overflowing weir, and for future numerical investigations, turbulence scales of the phenomena were investigated for both pressure measurements and PIV measurements. The analysis was performed focusing on the time-averaged quantities and evaluation of turbulence, for both pressures and velocities. Based on the understanding of the phenomena and experimental investigations, parameters affecting the hydraulic loading downstream of an overflowing structure had been recommended to be considered in further experimental studies of the phenomena.?