Transients in Pipes
(Lead Speaker: Professor Silvia Meniconi, University of Perugia, Italy - firstname.lastname@example.org)
Fluid transients, also called water hammer, are naturally generated elastic waves that occur in closed conduits whenever a rapid flow change takes place in the system. The same unique properties of fluid transients that both originated study inthis field (more than 150 years ago) and which continue to engage researchers and technology development in this field today are the following. First, the high celerity (speed of wave propagation) in pipeline systems means that relatively small changes in fluid velocity will produce large changes in pressure. In fact, fluid transients in pipelines can produce transient pressure heads in the order from tens to hundreds of meters. The water hammer name originated from the vibration and impact noise that is heard in the pipeline as it bucks and strains to contain the large magnitude pressure waves. Often the pressures are sufficient to cause permanent distortion of pipeline supports and in severe cases can lead to failure of pipe walls, pumps and turbines, environmental contamination from spilled fluids and flooding of urban roadways and other areas. Continued research is required to develop more ubiquitous, cost effective and efficient means of fluid transient suppression, especially since pipeline failures from transients continue to occur around the world.
Although classical water hammer theory is focused on the one dimensional plane wave transient mode, much recent research has demonstrated that three-dimensional shear and turbulence effects can significantly alter the nature of these waves when compared to the classic 1-d models. The mechanisms governing transient wave generation and propagation are also frequency and mode dependent, creating a myriad of complexities that have driven recent fundamental research in this area, and which are now giving rise to the development of efficient solution schemes capable of predicting the complex multi-modal evolution of these waves in pipeline networks. Ultimately, improved understanding of these complex pressure waves has opened up new and exciting technological possibilities for the near future where these pressure waves can be used as means of collecting, transmitting and receiving information within the fluid environment of the pipeline system in a manner that is analogous to the use of small amplitude electrical signals in smart electrical grids for fault diagnosis, collection of consumer usage information as well as network monitoring and control.