Alan Vardy’s work on fluid-structure interaction (FSI) in suspended pipe systems began in 1985 and spanned about 20 years. The work was well supported by the EPRSC and by an Advisory Group of industrialists and academics. Leadership of this topic has now passed to Dr Arris Tijsseling.
In Dundee, the focus of FSI research was on the behaviour of discretely supported pipe systems. On the one hand, externally induced pipe motion (caused by earthquakes or rotating machinery, say) can induce pressure fluctuations in the internal flow. On the other hand, pressure fluctuations in the internal flows can cause sudden movement of the pipe system. A well known example is the vibration of water pipes in buildings when a tap/faucet is turned off suddenly. This topic is especially relevant to industrial chemical and power plants, but it can also cause damage to underground pipes that are seemingly well supported. An example of a positive exploitation of pressure rise due to sudden valve closure is a pump known as a hydraulic ram. Typically, it is used to pump water from country streams to outlets at much greater elevations without any need for external power - other than the stream itself.
Dundee’s contribution
Vardy’s main contribution to FSI research has been the provision of definitive experimental data enabling clear distinctions to be drawn between cause and effect. Early experiments on a single straight pipe were undertaken by David Fan, initially as a PhD student when he simply dropped a vertical pipe onto a rigid base. Subsequently, as a Research Assistant, he applied his work to more practical configurations - horizontally suspended pipes with bends and junctions. Tijsseling followed on, extending the scope to include more complex geometries and studying complications such as cavitation. An especially pleasing outcome of the cavitation experiments was the measurement of negative absolute pressures in the water. Unlike solids, liquids cannot usually sustain pure tension so this was of special interest to us.
Despite the academic fun, the researchers and the Advisory Group were keen to remove some of the mystique of this topic in engineering practice. The EPSRC generously provided funding to enable the project outcomes to be interpreted in a design context and to support the development of an informative website. Much of this work was undertaken by another outstanding Research Assistant, Della Leslie. An fsi website, initially hosted at Dundee, is now hosted at the Technical University of Eindhoven to which Tijsseling moved after some years as a Research Fellow and then as a Lecturer at the University of Dundee.
The website includes downloadable software and it lists many papers published in international journals and conferences - from Dundee and from elsewhere.
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| Dundee FSI: impact by a long rod | Detail of impact location |
Selected References
Leslie-Milbourne DJ, Vardy AE & Tijsseling AS (2004) Transient FSI in a pipe system with elbow and tee junction, Proc 8th int conf on Flow-Induced Vibrations, Société Hydrotechnique de France, Paris, 5-9 July 2004, 355-360
Tijsseling AS & Vardy AE (2004) Time scales and FSI in unsteady liquid-filled pipe flow, Proc 9th int conf on Pressure Surges, BHRG, Chester UK, 24-26 March 2004, 135-15
Tijsseling AS & Vardy AE (2004) FSI and transient cavitation in a T-piece pipe, Proc 8th int conf on Flow-Induced Vibrations, Société Hydrotechnique de France, Paris, 5-9 July 2004, 373-378
Tijsseling AS & Vardy AE (2005) Fluid-structure interaction and transient cavitation tests in a T-piece pipe, Journal of Fluids & Structures, 20, 753-762
Tijsseling AS & Vardy AE (2005) 20 years of FSI experiments in Dundee, Proc int conf on Computational Fluid and Solid Mechanics, MIT, 14-17 June 2005, (Ed: KJ Bathe), Elsevier, 1014-1017
Tijsseling AS, Vardy AE & Fan DA (1996) Fluid-structure interaction and cavitation in a single-elbow pipe system,J Fluids & Structures, 10(4), 395-420
Tijsseling AS, Vardy AE & Leslie-Milbourne DJ (2005) Waterhammer in flexibly supported pipe systems, Portuguese Journal of Water Resources (Portuguese title: Revista Recursos Hidricos, APRH), 26(2), 17-23
Vardy AE, Fan DA & Tijsseling AS (1996) Fluid-structure interaction in a T-piece pipe, J Fluids & Structures,10(7), 763-786
Zhang L, Tijsseling AS & Vardy AE (1999) FSI analysis of liquid-filled pipes, J Sound & Vibration, 224(1), 69-99
