The transport mechanism as well as the extent and the shape of the scour upstream of a circular orifice is investigated under steady flow conditions for different sediment sizes and heads on the orifice. The main mechanism of sediment transport is found to be vortex-related, appearing randomly within the scour hole. The scour length, maximum scour width, and maximum scour depth are evaluated for various sediment sizes and under different heads on the orifice. The non-dimensional scour depth profiles along the orifice centreline are found to be similar. The non-dimensional scour depth profiles across the width of the scour hole at various locations upstream of the orifice are found to be similar as well. The flow characteristics related to the scaled centreline longitudinal velocity and the scaled position of the maximum longitudinal velocity are found to approach those for the unbounded orifice at the equilibrium scour condition.

Water infrastructure plays a crucial role in delivering freshwater for survival and economic prosperity of communities. Regrettably, drinking water pipeline infrastructures in the US and many other developed and developing countries are in a deteriorated state becoming increasingly prone to leakages, which are estimated to be $\ge 20\%$ . Although several sensor-based leakage-monitoring systems already have been developed to address this pressing challenge, the sustainability of such monitoring systems was never cross-checked, especially in the context of monitoring large-scale water-distribution systems. This paper thoroughly studies the life-cycle aspects of a vibration-based leak-detection technique, namely leak-detection index (LDI), accounting for its cost and energy consumption. The capabilities of this new technique have been demonstrated previously through an experimental campaign. In this paper, a follow-up sustainability evaluation is conducted after conceptual prototypes are developed for the real-world deployment of this new leakage-monitoring system. Batteries and solar panels are considered options for power supply. A representative water distribution network is used for estimating the life-cycle cost and energy consumption of leakage monitoring using the proposed prototypes. The sensitivity of cost and energy consumption to data sampling rate, data transmission rate, and sensor spacing are also evaluated in this study. The results presented in this paper will be of interest to researchers working on sensor-based monitoring systems for water infrastructures and to water utility managers.

In this study the discharge coefficient for circular orifices of different size in two different sizes of riser pipe is investigated experimentally. This type of outlet structure is common in detention ponds to achieve runoff volume control from developed areas in order to meet outflow discharge and water quality requirements. The discharge coefficient is determined by recording the drop in pond water level with time as water flows out of the orifice. The discharge coefficient is found to be a function of head over the orifice, location of the orifice above the floor of the tank, and the ratio of the orifice diameter to riser pipe diameter. The discharge coefficient increases as the head over the orifice decreases and height of the orifice above the floor of the tank decreases. The discharge coefficient reduces as the ratio of the orifice diameter to pipe diameter increases and eventually reaches an asymptotic value. Also, with all other variables being the same, the discharge coefficient is lower for lar...

A total variation diminishing Runge-Kutta discontinuous Galerkin finite element method for the solution of one-dimensional (1D) shallow water flow equations for natural channels is presented. The hydrostatic pressure force and the wall pressure force terms are combined to simplify the calculations and prevent unphysical flow attributable to improper treatment of the bottom slope term. The treatment of the combined term that appropriately accounts for the momentum flux is given. HLL and Roe Riemann solvers are assessed for the mass and momentum flux terms. Numerical tests are conducted using prismatic rectangular and nonrectangular channels as well as non prismatic channels and natural channel for dam break, supercritical flow, transcritical flow, and dry-bed problems. Slope limiters based on flow cross section area, water surface, and water depth are evaluated. The tests show that HLL and Roe solvers provide similar accuracy. However, the slope limiter based on flow area provides more accurate solutions for tests in nonrectangular and natural channels.

This paper presents the results of a computational fluid dynamics (CFD) model study of the hydraulics of groundwater flow and porous pipe underdrains. The study was conducted using a three-dimensional CFD model built in ANSYS Fluent. The model was validated by replicating previous experimental results of saturated subsurface flow (water surface level above the aggregate) for a 10.2-cm perforated pipe shrouded in loose laid aggregate. The CFD model consistently overpredicted the flow rate for a given head and aggregate depth by an average of 11%. After considering the effect of pipe perforation blockage due to aggregate, the average overprediction decreased to only 6%. The discharge coefficient for the perforated pipe computed using the CFD model was 0.54 compared with 0.49 from experiments. It was also found that the discharge was quite small at the upstream end of the pipe, with the bulk of the water entering the pipe in the vicinity of the outlet. Finally, the computational results showed that, ...