Vicente S. Fuertes

Pipeline start-up with entrapped air

A mathematical model for the assessment of the pressure head maxima that air pockets within a pipeline can originate on start-up is presented. This model is based on a general model addressing the ...

Design optimization of wastewater collection networks by PSO

Optimal design of wastewater collection networks is addressed in this paper by making use of the so-called PSO (Particle Swarm Optimization) technique. This already popular evolutionary technique is adapted for dealing both with continuous and discrete variables as required by this problem. An example of a wastewater collection network is used to show the algorithm performance and the obtained results are compared with those given by using dynamic programming to solve the same problem under the same conditions. PSO is shown to be a promising method to solve optimal design problems regarding, in particular, wastewater collection networks, according to the results herein obtained.

General Overview of Unaccounted for Water in Water Distribution Systems

The growing concern on improving the use of water in distribution systems, requires increasing the quality and the reliability in such systems. This paper presents a series of techniques aimed at reducing water losses and increasing the efficiency in the supply.

The Modelling of Water Distribution Systems

The decision making process when deciding which strategy to adopt must be based, in any activity, on good information. Broadly speaking, we can say that to elaborate a model of a network of water distribution consists in organizing adequately the available information about the water network, increasing the information if necessary and maintaining it updated, with the objective of feeding a hydraulic calculation program that permit us, as our principal task, to simulate the behaviour of the physical system which it represents as accurately as possible.

Computational models calibration: Experiences in environmental engineering studies

Mathematical models are a fundamental tool in the learning process of environmental engineering. These models need to be calibrated in order to be used by future engineers as a simulation tool for the represented problems. This paper deals with the concept of computational models calibration applied to higher environmental engineering studies. In this paper, we depict a methodology to calibrate water quality models, as an educational example that represents the environmental problem of dissolved oxygen in a stream. This methodology is based on defining two types of parameters involved in calibration. First, internal parameters appear in the equations from semi‐empirical estimations and can be found within some intervals. Genetic algorithms are proposed to estimate them. Second, experimental measurements enter into equations as external parameters. They affect the accuracy of the final solutions. Therefore, an uncertainty analysis has to be performed. Finally, a termination criterion for calibration has been proposed, based on the overlap between the confidence intervals of predicted and measured values. By developing this methodology, we provide awareness to our students of the importance of calibration of mathematical models so that they can apply them in their future simulation of environmental problems. Students identify the possible sources of uncertainty at each stage of the environmental model performance and apply them in this particular problem, Genetic Algorithm Techniques, as a computational tool to improve the accuracy of their model predictions.

Generalization of Pump Station Boundary Condition in Hydraulic Transient Simulation

In this paper, a generalized treatment of the equations describing the behavior of a pumping stat ion is presented. It enables the simulation of many reasonable combinations of elements within a pumping station, by using a single routine and one set of state data suitably maintained. Thus, it represents a unified algorithm massively solved that easily accommodates to virtually every condition in a pumping station. Besides, the interpolating method it uses allows to incorporate manufacturers information into dimensionless curves helping plausibly to produce more real results. The interest of the paper is mainly computational. Nevertheless, the scheme we propose enables the joint consideration of a wide range of elements in a pumping station without the need of including short reaches between them. In this way, it is claimed to represent a good improvement for existing packages to model transient analysis in networks.