Study of the hydraulic performance of stilling basins using physical and numerical models (Delft 3D) : case study : New Naga Hammadi Barrage on the Nile

This thesis aims to study the hydraulic performance and the flow conditions in a stillingbasin and examining if and how accurately the flow in the stilling basin could becomputationally modelled. Delft 3D software was used to simulate the sluicewaybehaviour of the New Naga Hammadi Barrage on the Nile River. 1D, 2DV (2DVertical) and 3D simulations have been used to study the sluiceway in two mainoperational cases fully open gate (during flood events) and partially open gate (in thenormal cases). Different scenarios have been studied; different sill levels, differentapron lengths with and without baffle blocks.The results of these models have been compared with the results of the hydraulic flumemodel which was built at the Hydraulic Research Institute (HRI) in Egypt, alsotheoretical analysis using formulas and charts from the existing literature was applied tocheck the numerical model results.In case of fully open gates Sigma and Z-Grids were used in studying the 2DV models.Z-Grid gave good results in simulating the water level drops over the sill and the headlosses as it considers the vertical acceleration and the non-hydrostatic pressure, whilstSigma grid showed insensitivity with the bed changes as it applies the shallow waterequations so it was decided not to use it in all other cases.Using the statistical analysis Z-Grid models showed good agreement with the physicalmodel results regarding the velocities in general, however it showed less accuracy nearthe bed due to the staircase representation of the bottom.In case of partially open gate 1D Model gave good results for the calibration of theradial gate opening particularly with low discharges.Some other aspects were tested in the models but not used for the model validation likelocal scour downstream the basin using Flooding and Cyclic schemes, dissipationenergy in case of baffle blocks existence (3D Models) and the head losses in case ofpartially open gates these aspects have been studied to open the way for further deepstudies in these areas