Sensitivity analysis of urban flood flows to hydraulic controls

Water Qualit

1d/2d porosity model for urban flood modeling

International audienc

Experimental investigation and performance analysis of Archimedes screw generator

The generation of renewable energy with Archimedes screw generators (ASG) transforming potential energy of fluid flow into mechanical energy is a growing technology suitable for low-head hydraulic sites. This paper presents an improved theoretical model linking screw performance to screw geometry and flow conditions. This model takes into account leakages, friction losses and variable fill levels. The modelled values of torques and efficiencies are in a fairly good agreement with experimental results obtained for a laboratory-scale screw. The downstream screw immersion is shown to impact ASG efficiency and an optimal immersion level is proposed. It has been found that fluid friction on the screw is not negligible. The analysis shows that a single value of the friction coefficient is suitable for modelling the screw performance under various flow conditions. The leakage phenomenon at under-filling flow conditions and friction forces in complex turbulent flows need to be further studied

Modeling sediment deposition from marine outfall jets

International audienceThis paper presents a two-dimensional model to study the sediment deposition from marine outfall jets. The introduced unidirectional coupling (fluid-sediment) is an appropriate choice in the case of low-concentrated particle-laden jets such as municipal wastewater discharge, where the concentration of particles is small enough and does not affect the hydrodynamic development of the jet in the nearfield. The sedimentation model takes advantage of the preferential concentration phenomenon. The deposition criterion states that the deposition of sediments begins when the vertical component of the entrainment velocity becomes smaller than the settling velocity. Once the deposition process begins, it is controlled by the settling velocity, entrainment velocity, volume flux, and sediment concentration. The deposition along the jet trajectory is expressed by an ordinary differential equation coupled with the liquid phase equations. Experiments of Lane-Serff and Moran [Sedimentation from Buoyant jets. J Hyd Eng. 2005;131(3):166-174], Cuthbertson and Davies [Deposition from particle-laden, round, turbulent, horizontal, buoyant jets in stationary and coflowing receiving fluids. J Hydr Eng. 2008;134(4):390-402], and Lee [Mixing of horizontal sediment laden jets [dissertation]. Hong Kong: University of Hong Kong; 2010], chosen from bibliography, are used to validate the model. These experiments cover the cases of horizontal and inclined buoyant jets in stationary ambient, horizontal buoyant jets in co-flow current and nonbuoyant horizontal jets in stationary ambient. Good agreement between the experiments and the obtained simulations is revealed

Simulation of subcritical flow at open-channel junction

International audienc