title: A new approach to investigate wave dissipation in viscoelastic tubes: application of Wave Intensity Analysis.
abstract: Wave dissipation in elastic and viscoelastic medium has been investigated extensively in the frequency domain. The aim of this study is to examine the pattern of wave dissipation in the time-domain using Wave Intensity Analysis. A single semi-sinusoidal pulse was generated in 8mm and 16mm diameter tubes; each is of 200cm in length. Pressure and flow measurements were taken at intervals of 5 cm along the tube. In order to examine the effect of the wall mechanical properties on wave dissipation, we also modified the wall of the 16mm tube; a thread of strong cotton was wound with a pitch of approximately 30&#176; around the circumference of the tube in the longitudinal direction. The separated forward pressure, wave intensity and wave energy were calculated using Wave Intensity Analysis. The amplitudes of the forward pressure wave, wave intensity and wave energy dissipated exponentially with distance. In the 8mm diameter tube, the dissipation of forward pressure, wave intensity and wave energy were greater than those in 16mm tube. For the same sized of tube, there was no significant difference in the dissipation of forward pressure, wave intensity and wave energy between the modified and normal wall tubes. It is concluded that the size of tube has a significant effect on the wave dissipation but the mechanical properties of the wall do not have a discernable effect on wave dissipation.
authors.affiliation: School of Engineering and Design, Brunel University, Uxbridge, Middlesex, UK, UB8 3PH.
authors.forename: J
authors.initials: J
authors.lastname: Feng
authors.forename: A W
authors.initials: AW
authors.lastname: Khir