Measurements of steady turbulent flow through a rigid simulated collapsed tube
Axial and transverse components of liquid velocity are measured by laser Doppler anemometer in a perspex tube that has been deformed at one point to resemble the shape of the throat of a partially collapsed flexible tube, conveying fluid while being compressed externally. The Reynolds number is 5900. The flow downstream of the throat consists of two side-jets with reverse flow extending all across the cross-section between them. The jets spread out around the central retrograde-flow zone, initially forming crescents of high-speed forward flow and then, at three diameters downstream, an almost complete annulus of forward flow around a central zone of lower-speed but now forward flow. Comparison is made between the features of this turbulent flow and those of a previously investigated laminar flow through the same geometry. In both, retrograde flow ceases between two and three diameters downstream of the centre of the throat. However, the laminar flow is annular at three diameters downstream, whereas here the jets remain influential at that station. The maximum normalised turbulence intensity exceeds 1.35.
KeywordsFlow separation Flow recirculation Laser Doppler Turbulence intensity
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- Aomatsu, T., Matsuzaki, Y., andIkeda, T. (1999): ‘Numerical calculation of phonation threshold pressure’,Proc. ASME Bioeng Conf.,BED 42, 16–20 June 1999, Big Sky, Montana, pp. 101–102Google Scholar
- Bertram, C. D., andGodbole, S. A. (1997): ‘LDA measurements of velocities in a simulated collapsed tube’,ASME J. Biomech. Eng.,119, pp. 357–363Google Scholar
- Bertram, C. D., Diaz de Tuesta, G., andNugent, A. H. (2001): ‘Laser Doppler measurements of velocities just downstream of a collapsible tube during flow-induced oscillations’ to be published inASME J. Biomech. Eng.,123 Google Scholar
- Griffiths, D. J. (1980): ‘Urodynamics — the mechanics and hydrodynamics of the lower urinary tract’ (Adam Hilger Ltd, Bristol)Google Scholar
- Ikeda, T., andMatsuzaki, Y. (1999): ‘A one-dimensional unsteady separable and reattachable flow model for collapsible tube-flow analysis’,ASME J. Biomech. Eng.,121, pp. 153–159Google Scholar
- Jensen, O. E. (1992): ‘Chaotic oscillations in a simple collapsible-tube model’,ASME J. Biomech. Eng.,114, pp. 55–59Google Scholar
- Ohba, K., Sakurai, A., andOka, J. (1989): ‘Self-excited oscillation of flow in collapsible tube. IV (laser Doppler measurement of local flow field)’. Technology Report, Kansai University, (31), pp. 1–11Google Scholar
- Shapiro, A. H. (1977): ‘Physiologic and medical aspects of flow in collapsible tubes’. Proc. 6th Canad. Cong. Appl. Mech., Vancouver, pp. 883–906Google Scholar
- Smaldone, G. C., andSmith, P. L. (1985): ‘Location of flow limiting segments via airway catheters near residual volume in humans’,J. Appl. Physiol.,59, pp. 502–508Google Scholar