Below are the brief introductions and profiles of lectures to be presented at the IAHR Training Course on Modelling and Software for Transient Flows organised by the IAHR Working Group on Transient Flows.
IAHR Training Course on Modelling and Software for Transient Flows
As this is the inaugural course of the new IAHR education initiative, I will use the first five minutes of the talk to introduce this initiative and provide a preview of the upcoming courses for the rest of 2025. I will then dedicate the remainder of the talk to addressing the following five questions. (1) This course will expose you to a wide a range of models from very simple 1-D models to 3-D models. What are the length and time scales that define the set of transient flow regimes and the domain of applicability of the various models? (2) This course deals with problems where Mach number << 1 and the majority (if not all) of the speakers will include compressibility in their models. Yet, many books and papers deny the role of compressibility in flows where Mach number << 1. In fact, a reviewer of research proposal recently stated “Mach number is between 0 and 0.0025 which is basically an incompressible fluid flow”! So, when is it necessary to include compressibility in our models and what criteria decides if compressibility is or is not important? (3) All inverse transient flow models are ill-posed; yet inverse transient models are routinely applied to infer model parameter estimation and perform defect detection with no apparent fuss. How come? (4) It is evident that incorporating physics in the development of data driven transient flow models is beneficial. But what physics to incorporate? (5) Models often agree well with laboratory data. What do we need to do to achieve similar level of agreement between models and field data?
In complex hydraulic infrastructures like water supply networks and storage hydropower plants challenging transient flows can occur during operation, which have to be simulated with uncertainties at the beginning of any project. The hydraulic infrastructures are briefly presented with focus on storage hydropower plants explaining the different alignment and lining options of the waterways with the actual trends when new pumped-storage power plants. The challenge of transient flows simulations will be highlighted taking into account the real behavior of the waterways in interaction with the hydraulic machinery. Technical mitigation measures with focus on surge tanks for managing transient flows and extreme pressures in the waterways are presented.
Profile
Anton Schleiss graduated in Civil Engineering from the Swiss Federal Institute of Technology (ETH) in Zurich, Switzerland and obtained a PhD on the topic of pressure tunnel design in 1986. After that he worked for 11 years for Electrowatt Engineering Ltd. (now AFRY) in Zurich and was involved in the design of many hydropower projects around the world. In 1997, he was nominated full professor and Director of the Laboratory of Hydraulic Constructions (LCH) at the Ecole Polytechnique fédérale de Lausanne (EPFL) and became honorary professor in May 2018. After having served as vice-president between 2012 and 2015 he was president of the International Commission on Large Dams (ICOLD) from 2015 to 2018. For his outstanding contributions to advance the art and science of hydraulic structures engineering he obtained in 2015 the ASCE-EWRI Hydraulic Structures Medal. The French Hydro Society (SHF) awarded him with the Grand Prix SHF 2018 and IAHR as honorary member in 2021. In 2024 he was listed by Int. Water Power & Dam Construction presents among the 75 most influential individuals in the hydropower industry. With more than 40 years of experience he is regularly involved as a consultant and expert in large water infrastructures projects including hydropower and dams all over the world. On behalf of ICOLD he is the scientific coordinator of the ETIP HYDROPOWER project funded by the EU Horizon Europe research and innovation program.
Bryan Karney
Bryon Singh
Hydraulic transient models are more demanding than their steady-state and EPS counter parts. One can easily get lost in the details and lose sight of the modelling objectives, which fundamentally is to make a better decision about system protection and risk management. This talk will review some of the challenges and unintended consequences that can arise when representing physical hydraulic systems in digital form and some practical steps for resolving them. Topics include: system conceptualization and model simplification, demand re-allocation, boundary condition representation and interaction, wave speed initialization, time step selection, among others.
Profiles
Bryan Karney graduated from the University of British Columbia with a B.A.Sc. degree in 1980 and a Ph.D. in Civil Engineering in 1984. He has been at the University of Toronto since 1987 and active in the consulting company HydraTek throughout that time. Bryan has almost 40 years of experience in providing hydraulic services on a wide range of fluid systems, including water, wastewater, storm, oil, gas, and jet fuel. Bryan has spoken and written widely on subjects related to water resource systems, energy issues, and hydrology. He has written numerous papers and has been awarded a number of teaching and research awards.
Bryon Singh is a Senior Hydraulic Specialist at HydraTek with almost 20 years of experience in the water and wastewater industry. Bryon received both his Bachelor’s and Master’s degrees in Civil Engineering at the University of Toronto and is a Licensed Professional Engineer in the Province of Ontario. Bryon has worked on hundreds of hydraulics-related projects in Ontario, across Canada, and internationally, with the projects types ranging from hydraulic and transient analyses to field monitoring studies as well as research and development. He is an expert with respect to the hydraulic modelling of water and wastewater systems, numerical transient modeling, the design and optimization of surge protection, and hydraulic field investigations.
Sam van der Zwan
During this short lecture on WANDA, we will be focussing on two aspects of hydraulic modelling in WANDA. The first item is boundary condition modelling. We will show that is modeler it is important to know different options for boundary conditions and when to use what. In this we will be looking into different options for the modelling of boundary conditions. We will also be looking into the possibility to model loop systems with temperature effects. From there on we will continue with the second item with is the WANDA control module. We will showcase some examples how it can be applied to district heating systems.
Profile
Sam van der Zwan has been working for more then 15 years at Deltares in the field of pipeline hydraulics. He has been involved in many surge studies, given courses on this subject and is member of the Technical Advisory committee of the international conference on pressure surges. He is also product owner and lead developer of the renowned water hammer software package WANDA.
Lina Sela
Lu Xing
Gerardo Riano
Modeling transient flow conditions in water distribution networks has become increasingly valuable for applications such as burst and leak detection, sensor placement, model calibration, and risk assessment. However, transient modeling remains challenging, as it is often confined to commercial software, limiting accessibility and usability for the broader community. This workshop introduces two open-source Python packages developed by the University of Texas at Austin to address these challenges and facilitate the integration of transient modeling into simulation-based applications. The first package, Transient Simulations in Water Networks (TSNet), utilizes the Method of Characteristics (MOC) to solve the partial differential equations governing unsteady hydraulics, enabling users to simulate various scenarios, including operational changes in valves and pumps, background leaks, and pipe bursts. Building on this foundation, Parallel Transient Simulation in Water Networks (PTSNET) introduces a novel parallel implementation of the MOC for networked systems, leveraging vectorization and distributed parallel computing (DV-MOC) to enhance scalability and computational performance. The workshop will also include a discussion of future directions to improve the accessibility, usability, and long-term support of these tools, as well as how the research community can contribute to advancing and maintaining open-source solutions for transient modeling in water networks.
Profiles
Dr. Lina Sela is an Associate Professor in Environmental Water Resources Engineering, in the Civil, Architectural and Environment Engineering department at the University of Texas at Austin. Dr. Sela’s research focuses on improving the efficiency of water distribution systems facing challenges related to finite water sources, aging infrastructure, and population growth. Her work relies on integrating the increasingly available digital information from distributed sensing devices with models to improve operations and management of water systems. She is a recipient of the NSF CAREER award and is an Associate Editor in the Journal of Water Resources Planning and Management.
Dr. Lu Xing is a Senior data scientist at Xylem Inc. Before Xylem, she earned her Ph.D. at the University of Texas at Austin. Her work focuses on leveraging numerical modeling, algorithm development, remote sensing, and artificial intelligence to promote the advancement of intelligent and resilient water infrastructure systems. Major areas of interest include water loss management, leak detection, facility operation optimization, Internet of Things (IoT) for water system management, and digital twins.
Dr. Gerardo Riano is a Postdoctoral Associate at Cornell Tech. He earned his Ph.D. in Civil Engineering at the University of Texas at Austin. His research advances resilient infrastructure systems by combining numerical modeling with scalable algorithms for faster analysis, inference, and optimization. He advocates for open-source software and is the primary developer and maintainer of MatSWMM and PTSNET. Dr. Riano’s interests lie in the fields of digital twins, the water-energy nexus, anomaly detection, and water systems management.
The presentation introduces the SIMSEN software, which enables the modelling of hydroelectric power plants from water intake to electricity generation. It accurately captures the transient behavior of waterways and associated systems by accounting for all types of hydraulic machines, the mechanical inertia of rotating equipment, electrical machines and related installations, as well as the overall control system for turbines and generators. As the software was originally developed for electrical applications, the modeling of pressurized pipe dynamics was naturally incorporated using an electrical equivalent scheme. The advantage of this finite difference based approach is that Kirchhoff's laws are used to automatically generate the sets of differential equations, which are then solved by time-domain integration using the 4th order Runge-Kutta method. The result is a unified differential equation set in matrix form which includes hydraulic, mechanical, electrical, and control systems.
Following extensive validation—first against Method of Characteristics-based software and later through site measurements—SIMSEN has become widely adopted in the hydropower industry. The software capabilities are illustrated with the transient analysis of the 880 MW Gouvães pumped storage power plant (PSPP) in Portugal, recently commissioned by Iberdrola. The adequate transient behavior of this PSPP was demonstrated taking advantage of the Hydro-Clone digital twin monitoring system, which rely on real-time SIMSEN simulation to compare simulation results and site measurements during the commissioning tests.ç
Profile
Dr Christophe Nicolet is managing director of Power Vision Engineering Sàrl, PVE, in St-Sulpice, Switzerland. He is also external lecturer at Ecole Polytechnique Fédérale de Lausanne, EPFL, in the field of “Flow Transients in Systems” for Mechanical Engineering at Master Degree. He graduated in Mechanical Engineering from EPFL in 2001 and obtained his PhD degree in 2007 at the EPFL Laboratory for Hydraulic Machines in the field of hydroelectric transients modeling. In 2007, he co-founded PVE, since then he provides consulting and expertise in the fields of hydraulic and electric transient analysis, power plant system stability, control system optimization, ancillary services capability optimization. With more than 20 years of experience in the field of hydraulic machinery and transients, he was involved in more than 20 Pumped Storage projects ranging from feasibility study to troubleshooting in Switzerland and abroad. He is also working group member of IEC-TC4 on hydraulic turbines of WG33 on pressure fluctuations and co-convenor of WG36 on hydraulic transients calculation.
WH80 may be used for computing the transient state conditions (commonly known as water hammer) in pumping systems, in hydroelectric power plants, and in pumped-storage schemes; software WHINPUT for preparing or modifying the input data file interactively; an on-line version for cloud computing (allowing lease as short as one month) and TRANSEPANET for input data prepared in EPANET format. For additional details, visit www.compapplications.com. Transient state conditions in a piping system may be produced by opening or closing valves, starting or stopping of pumps, loading or unloading turbines, or varying the discharge or pressure at specified locations with time. The software may also be used to study the governing characteristics of a hydropower plant for small or large load changes (since major non-linearities are included) and to optimize the settings of a turbine governor. The method of characteristics is used to compute transient conditions. Turbo-machines, control devices and other appurtenances are simulated by using the procedures outlined in Applied Hydraulic Transients, third edition, by M. H. Chaudhry, Springer, New York, NY., 2014. The software WH80, originally written in FORTRAN 90, has been converted into Python. Either English or SI units may be used for the system parameters. Input data may be entered manually or interactively by using a separate program WHINPUT, included in the package. To facilitate data input, free format is used. Piping system may be a series or a branching system. Systems having up to 100 conduits, 30 valves, 15 turbines, 15 pumps, 15 surge tanks, 15 one-way surge tanks, five air chambers, five cooling-water condensers and 90 air cavities may be analyzed. (Contact Computer Applications, Inc. for a code for the analysis of larger systems.) Each conduit may be divided into up to 1000 equal-length reaches. For the machine characteristics, data for 16 pumps and 11 turbines over a wide range of specific speeds is stored in the software for use as an approximation when such data is not available. Several options are available for printing the computed results. The computed transient pressures and flows at different cross sections and the flow and other conditions for different appurtenances, such as valves, turbines, pumps, and surge tanks may be saved for post-processing and plotting by other software of User’s choice. The initial steady-state conditions in the system for the specified discharge in different conduits may be computed by using WH, they may be specified as input, or they may be computed by simulating the system for the specified initial boundary conditions for a sufficient time for the conditions in the entire system to converge to the steady state. The software has been verified by comparing the computed results with the field measurements at a number of hydroelectric power plants and pumping systems. The User’s Manual has six chapters: Chapter 1 describes the specification of the system and the preparation of system data. The arrangement of input data, definition of various parameters, and different options for the printing and saving of computed results for post-processing are presented in Chapter 2. This is followed in Chapter 3 by a discussion of the verification of the software. A number of typical examples and how to run the software on your computer or via Cloud are presented in Chapter 4 through 6. A number of empirical relationships and equations, tables, and figures for the values of various parameters are presented in the Appendix.
Profile
Dr. Chaudhry received his MASc. and PhD in Civil Engineering from the University of British Columbia, Vancouver, Canada in 1968 and 1970 and his BSc. degree with Honors in Civil Engineering from the University of Engineering and Technology, Lahore, Pakistan in 1965. He has been serving at the Univ. of South Carolina (USC) as Associate Dean (International Programs), College of Engineering and Computing (2007 to present), as the Founding Director, Engineering Management Program (2012 to present), CEC Distinguished Professor of Civil Engineering (2019 to present), Mr. and Mrs. Irwin B. Kahn Professor (1998–2018) and as Chairman, Dept. of Civil and Environmental Engineering (1997-2008); at Washington State Univ. (WSU) as Professor/Associate Professor (1983-97) and as Director, International Development Projects, College of Engineering and Architecture (1990-94); Associate Professor, Dept. of Civil Engineering, Old Dominion Univ. (1979-83); as Senior Engineer/Engineer (1970-79), IPEC and B. C. Hydro and Power Authority, Canada; and as Assistant Design Engineer, Water and Power Development Authority, Pakistan (1965-66). His areas of specialization are modeling in water resources and fluid transients. He was awarded Doctor Honoris Causa and a campus street named after him by the Universidad Polytecnica Valencia, Spain, in 1999 (other ’99 recipients, Nobel Laureates Marcus and Saramago); elected as Distinguished Member, Amer. Soc. of Civil Engineers (ASCE) in 2016 (Highest honor of ASCE); Hunter Rouse Hydraulic Engineering. Award in 2008 (The most prestigious Water Resources Award by ASCE); the Hydraulic Structures Medal in 2024 (one of the top awards of ASCE); the Russell Research Award in 2009, Research Achievement Award, 2003 and Bert Storey Innovative Research Award in 2008 (The highest research awards of the university, college and department, respectively); Biedenbach Service Award in 2011; Leon Luck Award for Outstanding Faculty Member of the Dept. of Civil and Environ. Engineering, WSU in 1986, and the AT&T Award for Teaching Excellence, ASEE in 1989; and one gold and two silver medals for scholastic achievements. He has acted as a consultant in all six continents to organizations such as the United Nations, UNDP, US AID, US Army Corps of Engineers, California Dept. of Water Resources, Institute of Computer Applications in Science and Engineering, NASA Langley, Inter-American Development Bank/Instituto Costarricense de Electricidad, Costa Rica, Instituto Ecuatoriano de Electrification, Ecuador, World Bank/Punjab Irrigation Dept., various engineering firms, public utilities, and as an expert witness to law firms in the USA and Canada. He received research grants from NSF, FHWA, USAID, EPA, Corps of Engineers, NOAA, and other agencies. Presently as a PI, he has ongoing research grants and contracts on levee- and dam-breach modeling, funded by ERDC/US Army Corps of Engineers for $4 million, by NOAA/CIROH for $750 k and $266 k as PI and another $266 k as a Co-PI; and $1.5 million SCDOT project for technology transfer; and, as Co-PI, $2 million grant by NSF on levees. He recently completed a $3-million, NSF PIRE project on the modeling of flood hazards from dam breach and levee failure. Dr. Chaudhry has been Associate Editor, Journal of Hydraulic Engineering, American Society of Civil Engineers, since 1985 and he was the Associate Editor, Journal of Fluids Engineering, American Society of Mechanical Engineers, from 1980-84. He is a registered Professional Engineer in Texas and British Columbia, Canada, a Fellow, American Society of Civil Engineers, Diplomate, Academy of Water Resources Engineers, and a member of the American Society of Mechanical Engineers, and International Association for Hydraulic Research. He is the author of Open-Channel Flow, 3rd ed. (Springer, 2022, 563 pp); Applied Hydraulic Transients, 3rd edition (Springer, 2014, 583 pp.); co-author of Hydraulic Engineering, 2nd ed. (Wiley, 1998, 653pp); senior editor of Closed-Conduit Flow (Water Resources Publication, 1982, 416 pp), and Computer Modeling of Free-Surface and Pressurized Flows (Kluwer Academic Publishers, 1994, 741pp). He has edited seven volumes of conference proceedings and published over 150 journal and conference papers. Dr. Chaudhry has supervised 22 Post-doctoral Fellows/researchers, 21 doctoral and 15 Master’s theses, and has organized and lectured at several short courses in the USA and overseas.
The topic of this lecture is the three-dimensional numerical simulation methods for transient processes in hydropower stations and pumped storage power stations, a subject that has seen significant development over the past decade. We will discuss the computational frameworks that couples one-dimensional pipe systems with three-dimensional hydraulic turbines for transient process analysis. The lecture will also introduce the applications of this method in investigating several key mechanistic issues in hydropower and pumped storage systems, present case studies for demonstrating its utility in solving practical engineering problems, and conclude with an outlook on future research directions.
Profile
Prof. Dr. Yongguang Cheng is a full professor with School of Water Resources and Hydropower Engineering of Wuhan University, China, and a senior researcher at State Key Laboratory of Water Resources Engineering and Management. He is the director of Teaching Section of Hydropower Station and the deputy director of Research Institute of Hydropower Station Safety and Control.
He obtained a Ph.D. degree in engineering in 1998, a master's degree of engineering in 1995, and a bachelor's degree of engineering in 1992, all at Wuhan University of Hydraulic & Electric Engineering, China. As a senior visiting fellow, he visited the department of mathematics, Indiana University-Purdue University Indianapolis, USA, and Iowa Institute of Hydraulic Research (IIHR), the University of Iowa, USA. As a postdoctoral researcher, he studied at the Institute of Fluid Mechanics, Karlsruhe University, Germany, and Hohai University, China.
Prof. Dr. Cheng has been engaged in teaching and research of transient processes of hydraulic systems for over 30 years. He has led 8 National Natural Science Foundation of China (NSFC) projects, including the key projects "Evolution Mechanism of Pressure and Runner Force Fluctuations in Pump-Turbine during Transient Processes" and "Stability Mechanism and Control Strategy for Variable Speed Pumped-Storage Units Operating in Wide Power and Frequency Ranges". He presided over 40 industry projects on transient processes of pumped storage power stations, large water conveyance systems, and large hydropower stations. He developed a CFD based 1D-3D coupled simulation scheme for transient processes, to analyze the interactions of water hammer pressure, turbine flow patterns, pressure fluctuations, runner forces, shaft vibration, and runner fatigue. He has published more than 150 related academic papers and owned dozens of patents.
Shawn Huang
Nathan Gerdts
Hydraulic transients in a water distribution system are unique, arising from frequent operational adjustments like pump startups, shutdowns, and valve operations, which respond to the system's constantly changing demands. This presentation will provide an overview of a standard procedure for creating a well-represented transient simulation model using InfoWater Pro, while also addressing common pitfalls to avoid. Surge protection strategies will be assessed for both existing and new water distribution systems, with each type of surge protection device reviewed in terms of its applicability.
Profiles
Shawn Huang completed his Ph.D. in Civil Engineering with a focus on Numerical Simulation at Pennsylvania State University in 2006. Since then, he has been actively engaged in the water and wastewater industry. As a Technical Support Manager for Autodesk hydraulic simulation products for many years, he led a team of product specialists to ensure the delivery of exceptional customer service. Currently serving as the Software Development Manager at Autodesk, Shawn oversees the development of water system simulation products, including InfoWater Pro and InfoSurge.
Nathan Gerdts is Product Manager in the Water Infrastructure team at Autodesk focusing on Water Distribution products. Since receiving his master’s degree from the University of Wisconsin Madison, Nathan has lead implementation projects and advised in sales with Innovyze for 9 years, spanning model building to real-time operational modeling.
In recent years, countries worldwide have intensified efforts to adopt renewable energy. China, in particular, has integrated a substantial amount of wind and photovoltaic (PV) output power into its grid. By the end of 2024, the total installed capacity of wind and solar power in China accounted for over 40% of the nation’s total power capacity, reaching approximately 1.35 billion kilowatts. However, the inherent output fluctuations of wind and solar energy present significant challenges to grid safety and stability. Pumped storage power stations have emerged as one of the most effective solutions to support grid reliability. In grids with high renewable energy penetration, the demand for rapid adjustment capabilities from pumped storage units has surged. This necessitates not only faster transitions between operational conditions but also robust safeguards for unit safety and stability.
To address these challenges, we developed a framework for simulating, analyzing, and optimizing three-dimensional fluid flow within the hydraulic systems of pumped storage units during transient processes. Using three-dimensional computational fluid dynamics (CFD) commercial software and secondary development modules, we formulated governing equations for rotational speed during operational transitions. This framework enables dynamic mesh adaptation and alignment in response to guide vane movements, facilitating high-fidelity simulations of the 3D flow field within the hydraulic system. Through these simulations, we obtained detailed insights into hydraulic characteristics and flow field evolution throughout transient processes. These insights include external characteristics such as rotational speed, flow rate, and torque of the unit, as well as internal characteristics like pressure distribution, flow patterns, and runner forces within the entire flow passage. These findings aid in evaluating hydraulic stability, particularly for critical components like the runner.
To further investigate transient flow dynamics, we applied advanced fluid mechanics methodologies, including our proposed rigid vorticity transport equations, to analyze the effects of rigid vorticity and shear flow on runner performance. We validated our framework using a 3D simulation case study based on data from major Chinese pumped storage stations, demonstrating the successful optimization of operational condition switching times while maintaining pressure fluctuations and runner forces within stability thresholds. This framework provides distinct advantages over traditional methods, enabling detailed, fine-grained assessment of hydraulic stability during transient processes in pumped storage systems.
Profile
Prof. Dr. Kan Kan is an associate professor with School of Electrical and Power Engineering of Hohai University, China. He is the director of Research Institute of Pumped Storage Technology. He earned a Ph.D. in Engineering (Water Conservancy and Hydropower Engineering) in 2019 and a Bachelor of Engineering (Thermal Energy and Power Engineering) in 2012, both from Hohai University in China. As a visiting Ph.D. student, he visited the Department of Mechanical Engineering and St. Anthony Falls Laboratory, University of Minnesota - Twin Cities, USA, from 2016 to 2018.
Dr. Kan specializes in performance analysis of hydraulic machinery for pumped-storage power stations, hydropower stations, and pump stations. He has secured two research grants from the National Natural Science Foundation of China and led scientific projects for major Chinese hydropower companies, including the China Three Gorges Corporation and China Huadian Corporation. With a publication record of over 100 papers, six of which have been recognized as ESI Highly Cited Papers (Clarivate Analytics). His work has been cited more than 1,400 times on Google Scholar. Dr. Kan was honored as one of the World's Top 2% Scientists by Elsevier. Additionally, he was selected for the Jiangsu Association for Science and Technology's Youth Science and Technology Talent Support Program in 2023. Dr. Kan has received three provincial/ministerial-level awards, including being a key contributor (second-ranked) to the 2024 China Electric Power Science and Technology Progress Award (First Class). Dr. Kan has developed a CFD-based method for the transient process of pumped storage units, which accelerates the conversion rate while ensuring hydraulic stability, such as controlling pressure pulsations and runner forces during the transient process.
There are many hydraulic transient software packages around the world. In fact, in 2005 Ghidaoui et al, presented brief descriptions of eleven well known computer models, and prior to proceed listing basic details of which one, they gave the following advice: Due to space limitations, all the water hammer software packages now readily available could not be included in this summary. The reader is encouraged to search out alternatives on the Internet prior to selecting one of the models described herein. And that is, indeed, very true. Searching at the website with the text chain “software packages to perform hydraulic transient analysis” can be found the mentioned in Guidaoui et al, 2005 but also many others. Therefore, the engineer who is looking for this tool, has a wide offer to select the more appropriate one to their needs. A decision that, indeed, must be complemented by the corresponding cost – benefit analysis because most of them are not especially cheap.
Therefore, and linked to this talk, a key question arises from the preceding introduction. Considering a so wide offer, what reason justifies performing transient analysis with ALLIEVI? The answer is, in my view, short and clear. Like EPANET, the most famous and used hydraulic software, ALLIEVI is, as well, a friendly public domain computer model. It is important underline that, in the best of my knowledge, there is not any other public domain so complete and friendly as ALLIEVI is. Obviously, it is more complex than EPANET, because transient analysis problems require many complementary data (as the wave celerity) and includes a lot of protection devices (e.g. air chambers, surge tanks, air relief valves, etc.) not required by EPANET. On the contrary, most of the EPANET’s elements are modelled as well in ALLIEVI, a package developed along one decade as a joint venture between the ITA of the Universidad Politécnica de Valencia and Dr. Edmundo Koelle from Sao Paulo University (Brasil).
In ALLIEVI, the numerical approach to solve water hammer equations is, as most of the commercial packages, the method of characteristics (MOC), very well tested, numerically efficient accurate and rather simple to program. Without doubt, is the most popular method to face this problem. The ALLIEVI full version can be downloaded free of charge from its web page (https://www.allievi.net/). It is complemented with didactic material to show its use and supported with practical examples.
Its main features are:
Public domain software
Can analyse simple and complex systems (networks), without limit of nodes.
ALLIEVI includes most of the protection devices used in the real world. Furthermore, real data, as pumps characteristic curves, air valves, and many other devices, can be easily imported.
It includes assistant modules to help the assessment of unknown relevant parameters (as pump’s inertia flywheel, wave celerity, air chamber initial pressure…)
Most of these devices (as check valves) are dynamically modelled.
Several scenarios can be simultaneously analysed and, therefore, compared (systems without and with an element protection, different law closures, etc) making easier to find the best solution.
Able to import EPANET file networks
The steady state of the system (the starting point of the transient analysis) is calculated by ALLIEVI using the MOC.
Results can be easily shown graphically, making easier to prepare the report with the results.
To simulate how the transient is affected, air valves and break points can be included in the original system.
Water column separation is detected and modelled.
Can be used to analyse water hammer problems in hydroelectric power plants.
Etc.
From the preceding summary, the objective of this short talk (50 minutes) is, through different examples, to present a software package that has been widely checked in many practical installations. From this introduction, the attendants can learn if this computer model is the tool they are looking for performing transient analysis in a near future.
Profile
The milestones of the academic career of Enrique Cabrera are:
1. Industrial Engineer, 1970.
2. Master’s degree on Physics, 1974.
3. Doctor degree (with his PhD dissertation on water hammer), 1976.
4. Full professor of Fluid Mechanics at the Polytechnic University of Valencia, 1981.
5. Since 2019, emeritus professor at the same University.
His 50 years of professional life have been devoted mainly to two well linked fields, the urban water engineering and the pressurized water transport systems. His main effort has been put in solving real problems from an academic perspective. He has authored 350 technical papers, 60 of them published in SCI journals. He has edited 32 books (most of them Proceedings of International Conferences and International Courses he has chaired in Valencia) and contributed to over 50 more. During the last 25 years, being fully aware that the solutions of real and complex water problems are strongly dependent on socio-economic frameworks and water policies, is paying a growing attention to these issues. As a result, he has published over 100 opinion essays on water problems in the most important Spanish daily Journals.
Last, given the progressive decline of the education in general and the university training in particular, what he is most proud of his professional career is of his teacher’s work. First from the chair of Fluid Mechanics and later as a promoter of postgraduate courses in the urban hydraulics field, attended by over 2000 professionals. This task has been recently extended to policy makers, that must take important decisions without the adequate education and background. His last book “Guidelines for a sustainable urban water management”, published in 2024, is devoted to fulfilling this knowledge gap, right now, but even more in the near future, the most pressing educational need to solve adequately the main problems of the water engineering field.
The AFT Impulse modeling software has a long history of applications in municipal and industrial systems. This session will begin with a discussion of the assumptions used in AFT Impulse and the scope of capabilities. For above ground piping the transient hydraulic forces must be understood so proper pipe supports can be designed. An overview of assessing transient pipe forces will be given. Moving from simplified academic examples to real world systems can involve an immense jump in complexity. A complicated LNG marine offloading system will be discussed with 30+ transient events which occur within 30 seconds. Finally, two case studies will be reviewed. The first is a municipal water pumping station upgrade in Barcelona, Spain where the engineers measured the transients after pump trips using different check valve designs. The second is an industrial system in a Jamaican alumina refinery “Digester Blow-Off” system pumping a caustic, high- temperature alumina slurry. A manual valve experienced a catastrophic break of the valve stem. This led to a slam of the valve disk which sent a surge transient wave back towards the upstream pump and exploded the pump casing.
Profile
Trey Walters, P.E., is the Founder and Chairman of Applied Flow Technology in Colorado Springs, Colorado, USA. AFT develops simulation software for fluid transfer systems. At AFT Mr. Walters has developed software in the areas of incompressible and compressible pipe flow, waterhammer, slurry systems, and pump system optimization. He has performed and managed thermal/fluid system consulting projects for numerous industrial applications including power, oil and gas, municipal water, chemicals and mining. He actively teaches training seminars around the world. Mr. Walters founded AFT in 1993. He has nearly 40 years of experience in thermal/fluid system engineering. He has published over 30 papers and articles. Mr. Walters’ previous experience was with General Dynamics in cryogenic rocket design and Babcock & Wilcox in steam/water equipment design. Mr. Walters holds a BSME (1985) and MSME (1986), both from the University of California, Santa Barbara. He is an ASME Fellow.
Slavco Velicov
Proper design of water transport and distribution systems in both urban and rural areas requires careful consideration of hydraulic transients. Hydraulic transients (also known as water hammer or surge) are pressure fluctuations caused by a rapid change in fluid flow rates and velocities. The magnitude of the event is directly proportional to the change in inertia of the flowing fluid. Neglecting these critical aspects can lead to devastating consequences such as damage to pipes and equipment, endangerment of operator safety, and significant loss of capital investment.
Join us to learn the main principles of water hammer effect, understand the underlying mathematical model and numerical methods to solve this phenomenon, and finally explore how state-of-art software technologies can analise, simulate and protect water transport and distribution systems. The session will provide a detailed overview of Bentley Hammer software tool for simulation and analysis of transient flows. We will also feature few case studies of water transient analysis and surge protection measures of water transport and distribution systems in practice.
Profile
Slavco Velickov works as a global water industry director at Bentley Systems where and heads up a team of water professionals that deliver Bentley’s water digital twin solutions globally. Slavco further develops new markers and business opportunities with strategic partners and alliances.
He is a chartered engineer and has over 25 years of experience in the water industry in all phases of infrastructure projects development, financing, and implementation. Slavco holds a bachelor’s degree in civil hydraulic engineering with post graduate specializations in hydro-informatics and business development. His Ph.D. is from the Technical University in Delft, The Netherlands.