Abstract:The following work presents a multivariate statistical technique applied to the control of water inflows into district metering areas (DMA) of urban networks. This technique, called Principal Component Analysis (PCA), allows for a sensitive and quick analysis of the inflows into a DMA without hassling mathematical algorithms. PCA technique simplifies the original set of flow rate data recorded by the SCADA system, synthesizing the most significant information into a statistical model which is able to explain most of the behaviour of the water distribution network. PCA technique also allows for the establishment of control charts that help system operators in the identification of anomalous behaviours regarding water use, bursts or illegal connections. The described technique has been proved to offer high detection sensitivity to bursts or other unexpected consumptions.

Filling and emptying pipeline systems involve the movement of large volumes of water and air. Water transients occurring during these operations can originate large pressure peaks that can severely damage distribution networks. Entrapped air, depending on the circumstances, can have a damping or amplifying effect on these undesirable pressure peaks. Unfortunately, too often, the complexity of the phenomenon makes it difficult to obtain a fully reliable prediction on when air pockets will mitigate or accentuate water transients. For such prediction, equations governing the movement of the water column and the behaviour of the air pockets must be combined and, for practical reasons, simplified. These simplifications conventionally lead to questionable hypotheses (e.g. normal cross-section of water-air interface) required to solve the numerical model with a reasonable calculation time. Furthermore, the value of some of the parameters used in the numerical model cannot be calculated nor measured and need to be determined through a calibration process. Inevitably, this circumstance will lead to an even higher uncertainty of the results. With the aim of overcoming most of the aforementioned uncertainties, this paper summarises a complete set of tests conducted at WL | Delft Hydraulics. These tests were satisfactorily simulated by means of a tailored numerical model that includes a set of parameters whose values (the main obstacle to be overcome) were determined by means of a calibration process. The experimental setup (a large-scale facility) consisted of a single steep pipeline with an air valve installed at its top end. Air release through different air valves were tested under different conditions while the main variables (flow rate and pressure) were registered continuously at several points along the pipe. Lastly, and in order to be able to provide air valve manufacturers with helpful guidelines, the relevance of the parameters was evaluated by means of a sensitivity analysis.

ABSTRACT:To determine the influence of geometry on the hydrodynamic behavior of Venturi injectors, using computational fluid dynamics techniques, we studied, at