Wave propagation in flexible tubes

Wave dissipation was previously investigated intensively in the frequency domain, in which the dissipation of waves is described as attenuation of pressure pulse decay with respect to the frequency or harmonics. In this thesis, wave dissipation, including decay of pressure pulse, peak of wave intensity and wave energy, is investigated in the time domain using wave intensity analysis (WIA). Wave intensity analysis benefits to this research in several aspects including: 1) WIA allows for wave dissipation investigated in the time domain; 2) WIA does not make any assumptions about the tube's wall non-linearity and the analysis takes into account the effects of the vessel's wall viscoelastic properties, convective, frictional effects and fluid viscosity; 3) WIA offers a technique (separation) to study wave dissipation in one direction whilst taking into account the effect of reflections from the opposite direction; 4) The physical meaning of wave intensity provides a convenient method to study the dissipation of energy carried by the waves along flexible tubes. In this research, it is found that the degree of dissipation in flexible tube were not only affected by the mechanical properties of the wall property and viscosity of liquid but also by the other factors including initial pressure and pumping speed of piston as well as direction of wave in relation to direction of flow. Also an new technique to separate waves into forward and backward directions only using diameter and velocity might potentially be used to separate the waves in both directions non-invasively based on the non-invasive measurement of diameter (wall movement) available.

Grantor dc:publisher

Brunel University School of Engineering and Design PhD Theses

Year dc:date.issued

2008

Author dc:creator

• Feng, Jiling

Advisor dc:contributor.advisor

• Khir, A

• Wave dissipation
• Pressure pulse decay
• Wave intensity analysis (WIA)

Language dc:language.iso

en

Repository record dc:identifier.uri

http://bura.brunel.ac.uk/handle/2438/5367

OAI identifier oai:identifier

oai:bura.brunel.ac.uk:2438/5367