2026-09-18T18:43:43Zhttps://bura.brunel.ac.uk/oai/request

oai:bura.brunel.ac.uk:2438/53672014-11-01T12:38:32Zcom_2438_22com_2438_58col_2438_154col_2438_3672

Khir, A Feng, Jiling 2011-06-21T12:43:11Z 2011-06-21T12:43:11Z 2008 http://bura.brunel.ac.uk/handle/2438/5367 This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. 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. Submitted by Otue Ekong (lbsrooe@brunel.ac.uk) on 2011-06-21T12:42:34Z No. of bitstreams: 1 FulltextThesis.pdf: 34606776 bytes, checksum: 11ad56a96772307ee0b31ad9a3f82f26 (MD5) Approved for entry into archive by Otue Ekong(lbsrooe@brunel.ac.uk) on 2011-06-21T12:43:11Z (GMT) No. of bitstreams: 1 FulltextThesis.pdf: 34606776 bytes, checksum: 11ad56a96772307ee0b31ad9a3f82f26 (MD5) Made available in DSpace on 2011-06-21T12:43:11Z (GMT). No. of bitstreams: 1 FulltextThesis.pdf: 34606776 bytes, checksum: 11ad56a96772307ee0b31ad9a3f82f26 (MD5) en Brunel University School of Engineering and Design PhD Theses http://bura.brunel.ac.uk/bitstream/2438/5367/1/FulltextThesis.pdf Wave dissipation Pressure pulse decay Wave intensity analysis (WIA) Wave propagation in flexible tubes Thesis