Publications

Analysis of Siphonic Roof Drainage Systems with EPANET

Analysis and design of siphonic roof drainage systems are usually performed with specific software developed by the system’s manufacturers. An experimental study was carried out to verify if a general software for the analysis of hydraulic pressurized pipe networks can be used to analyze a siphonic roof drainage system. A test model was built and tests were conducted to compare the prototype results with simulation runs in EPANET. A new EPANET data model was developed to overcome software limitations for the siphonic drainage systems analysis. Considering the results, less than 5% of average error was observed between the measures in the real test model and the simulation results, which can be attributed to measurement error. To validate the EPANET data model, it was compared with a specific software that analyzes siphonic roof drainage systems. It can be concluded that EPANET is a software that can be used to analyze and, therefore, to design, siphonic roof drainage systems in buildings.

Air valves behavior. Comparison between compressible and incompressible flow

No abstract is provided for this article.

Pathogen intrusion flows in water distribution systems: according to orifice equations

Research Article| June 18 2015 Pathogen intrusion flows in water distribution systems: according to orifice equations Jesús Mora-Rodríguez; Jesús Mora-Rodríguez 1Geomatics and Hydraulic Engineering Department, Universidad de Guanajuato, Av. Juárez No. 77, Centro, 36000 Guanajuato, Mexico Search for other works by this author on: This Site PubMed Google Scholar Xitlali Delgado-Galván; Xitlali Delgado-Galván 1Geomatics and Hydraulic Engineering Department, Universidad de Guanajuato, Av. Juárez No. 77, Centro, 36000 Guanajuato, Mexico Search for other works by this author on: This Site PubMed Google Scholar Josefina Ortiz-Medel; Josefina Ortiz-Medel 1Geomatics and Hydraulic Engineering Department, Universidad de Guanajuato, Av. Juárez No. 77, Centro, 36000 Guanajuato, Mexico Search for other works by this author on: This Site PubMed Google Scholar Helena M. Ramos; Helena M. Ramos 2Civil Engineering Department and CEris, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049–001, Lisbon, Portugal E-mail: hr@civil.ist.utl.pt Search for other works by this author on: This Site PubMed Google Scholar Vicente S. Fuertes-Miquel; Vicente S. Fuertes-Miquel 3Hydraulic and Environmental Engineering Department, Universitat Politècnica de València, Camino de Vera, s/n. 46022, Valencia, Spain Search for other works by this author on: This Site PubMed Google Scholar P. Amparo López-Jiménez P. Amparo López-Jiménez 3Hydraulic and Environmental Engineering Department, Universitat Politècnica de València, Camino de Vera, s/n. 46022, Valencia, Spain Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2015) 64 (8): 857–869. https://doi.org/10.2166/aqua.2015.121 Article history Received: September 07 2014 Accepted: May 06 2015 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation Jesús Mora-Rodríguez, Xitlali Delgado-Galván, Josefina Ortiz-Medel, Helena M. Ramos, Vicente S. Fuertes-Miquel, P. Amparo López-Jiménez; Pathogen intrusion flows in water distribution systems: according to orifice equations. Journal of Water Supply: Research and Technology-Aqua 9 December 2015; 64 (8): 857–869. doi: https://doi.org/10.2166/aqua.2015.121 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Pathogen intrusion may occur in water pipes when negative pressures allow external flows to enter through failures or leaks and then mix with safe water. Based on the Fixed and Variable Area Discharge (FAVAD) theory and the orifice equations, an analysis is proposed to estimate the intrusion flow across defects in pipes considering different types of failure. The equivalent diameter of different round hole failures was considered in order to obtain the dimensions of the split failures that presented the same pressure drop. In addition, experimental scenarios were made with external porous media to model the intrusion flow in buried pipes. An inverse method for the orifice equation is proposed to obtain the intrusion flows generated by the variations of two section failures produced by the pressure drop inside the pipe. The orifice equation properly represents the intrusion flow by adjusting the discharge coefficient. Furthermore, the considerable variations in the failures area with negative pressures should be taken into consideration in the expressions that estimate the intrusion flow. buried pipes, failure pipes, FAVAD, physical model © IWA Publishing 2015 You do not currently have access to this content.

A fuzzy model for shortage planning under uncertainty due to lack of homogeneity in planned production lots

Lack of homogeneity in the product (LHP) affects several sectors like horticulture, reverse logistics, furniture, ceramics and leathers, among others. Productive processes with LHP are characterized by manufacturing units of the same finished good (FG) with certain attributes that differ and are relevant to customers. This aspect leads to the existence of different subtypes of the same FG in each production lot, which provides homogeneous sublots. Due to inherent LHP uncertainty, the size of each homogeneous sublot is not known until produced. LHP becomes a problem when customers order several units of the same FG and require homogeneity among them; i.e., being served with the same subtype. Like inherent LHP uncertainty, discrepancies between planned homogeneous quantities and the real ones is quite usual. This means it is impossible to serve committed orders with the previously defined requirements of quantity, homogeneity and due date, which brings about a shortage situation. In this paper, a fuzzy mixed integer linear programming model is proposed to support shortage planning in environments with LHP (LHP-FSP model). The LHP-FSP model aims to maximize the profits of served orders by reallocating the quantities of subtypes in stock and the uncertainty future ones in the master plan among the already committed orders. One of the main contributions of the paper is to model the fuzzy interdependent coefficients that represent the fraction of each homogeneous sublot. Finally, experiments based on realistic data from a ceramic company have been designed to validate the model and to analyze its behavior in different scenarios.

Predictive Analysis for U-Tube Transient Flow Events: A Digitalisation Framework

This study presents a methodology for the digitalisation process for analysing transient flow phenomena in a U-tube. It comprises several layers, including the characterisation of liquid oscillation dynamics, image segmentation for experimentally determining variations in the meniscus position, and the integration of machine learning techniques with analytical solutions. The position, velocity, and acceleration of the meniscus are obtained using image-processing methods and subsequently compared with the corresponding analytical predictions. The proposed methodology accurately represents the existing hydraulic conditions, incorporating both Newtonian and Ogawa friction models. To assess model performance, the index of agreement was employed to compare analytical and experimental results. The findings indicate a systematic error of 2.2 mm ± 3 pixels when using the Ogawa friction model, which corresponds to the best model for predicting this hydraulic behaviour. Finally, the implementation of machine learning techniques demonstrates considerable potential for predictive analysis, with statistical measures showing coefficients of determination above 0.997 and consistently low Root Mean Square Error values.

Comparison of evolutionary algorithms for design of sewer systems

No abstract is provided for this article.

Numerical modelling of pipelines with air pockets and air valves

This work considers the behaviour of air inside pipes when the air is expelled through air valves. Generally, the air shows isothermal behaviour. Nevertheless, when the transient is very fast, it shows adiabatic behaviour. In a real installation, an intermediate evolution between these two extreme conditions occurs. Thus, it is verified that the results vary significantly depending on the hypothesis adopted. To determine the pressure of the air pocket, the most unfavourable hypothesis (isothermal behaviour) is typically adopted. Nevertheless, from the perspective of the water hammer that takes place when the water column arrives at the air valve and abruptly closes, the most unfavourable hypothesis is the opposite (adiabatic behaviour). In this case, the residual velocity with which the water arrives at the air valve is higher, and, consequently, the water hammer generated is greater.

Mathematical modelling of the order-promising process for fruit supply chains considering the perishability and subtypes of products

This paper proposes a mixed integer mathematical programming model to support the complex order promising process in fruit supply chains. Due to natural factors, such as land, weather or harvesting time, these supply chains present units of the same product that differ in certain relevant attributes to customers (subtypes). This becomes a managerial problem when customers require specific subtypes in their orders. Additionally, the deterioration of the original characteristics of subtypes over time generates waste and gives rise to a shelf life-based pricing policy. Therefore, the developed model should ensure that customers are served not only the quantities and dates, but also the required homogeneity and freshness. The model aims to maximise two conflicting objectives: total profit and mean product freshness. The novelty of the model derives from considering both homogeneity in subtypes as a requirement in customer orders and the traceability of product deterioration over time. Different scenarios are defined according to the weight assigned to each objective, shelf-life length and pricing policy in a rolling horizon scheme. The numerical experiments conducted for a real orange and tangerine supply chain, show the model’s validity and the conflicting behaviour of the two objectives. The highest profit is made at the expense of the lowest mean freshness delivered, which is reinforced by the narrower the price variation with freshness. Finally, the positive impact of prolonging the product’s shelf life on both objectives is shown.

CFD and 1D simulation of transient flow effect on air vessel

Discussion of “Transient Flow in a Rapidly Filling Horizontal Pipe Containing Trapped Air” by F. Zhou, F. E. Hicks, and P. M. Steffler

Discussion of “Numerical Modeling of Mixed Flows in Storm Water Systems: Critical Review of Literature” by Samba Bousso, Mathurin Daynou, and Musandji Fuamba

No abstract is provided for this article.

Computational models calibration: Experiences in environmental engineering studies

Abstract 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. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 795–805, 2011

Design of Pumping Stations Using a Multicriteria Analysis and the Application of the AHP Method

The pumping station is a very important hydraulic system in urban water supplies because the pumps raise the water head, ensuring the minimum pressure required in drinking water systems. In the design of a pumping station, one of the most important criteria is the number of pumps. However, in the traditional design, this criterion is defined arbitrarily. The other criteria are defined from the number of pumps and can produce a design that is not optimal. In addition, the traditional design does not consider the importance of the environment in choosing the pumps. The objective of this paper is to define a new design methodology for pumping stations. It has been developed using a multicriteria analysis in which nine criteria are evaluated. The application of the analytic hierarchy process (AHP) allows for finding an optimal solution. These design criteria have been associated in three cluster factors: technical factors; environmental factors; and economic factors. The results obtained allow us not only to validate the methodology but also to offer a solution to the problem of determining the most suitable model and the number of pumps for a pumping station.

Evolutive techniques applied to water quality models calibration

No abstract is provided for this article.

Design of Water Distribution Networks using a Pseudo-Genetic Algorithm and Sensitivity of Genetic Operators

Using the Set Point Concept to Allow Water Distribution System Skeletonization Preserving Water Quality Constraints

Water distribution networks were included in the catalogue of critical infrastructures by different institutions as the European Council. One of the vulnerabilities of a water distribution networks consists of the contamination due to accidental or provoked events. Therefore, it is increasingly common to develop water quality models which allow the study of these threats. Many hydraulic models use algorithms with a high computational cost. Therefore, any strategy to accelerate these algorithms is an important contribution to the problem. This paper proposes a method to simplify branched areas of the network without losing information regarding water quality.

Pipelines with entrapped air pockets. Comparison between adiabatic and isothermal flow

Dimensionado de depósitos domésticos de aguas pluviales utilizando series temporales de datos

Resumen es: Los sistemas domesticos de aprovechamiento de lluvia se estan recuperando como una opcion alternativa al suministro desde las redes generales de distribu...