Curtin University Homepage
  • Library
  • Help
    • Admin

    espace - Curtin’s institutional repository

    JavaScript is disabled for your browser. Some features of this site may not work without it.
    View Item 
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item

    Parametric stability and dynamic buckling of an encapsulated microbubble subject to acoustic disturbances

    Access Status
    Fulltext not available
    Authors
    Tsigklifis, Konstantinos
    Pelekasis, N.
    Date
    2011
    Type
    Journal Article
    
    Metadata
    Show full item record
    Citation
    Tsigklifis, K. and Pelekasis, N. 2011. Parametric stability and dynamic buckling of an encapsulated microbubble subject to acoustic disturbances. Physics of Fluids. 23 (1): pp. 012102-012102.
    Source Title
    Physics of Fluids
    DOI
    10.1063/1.3536646
    ISSN
    1070-6631
    School
    Department of Mechanical Engineering
    URI
    http://hdl.handle.net/20.500.11937/56062
    Collection
    • Curtin Research Publications
    Abstract

    Stability analysis of the radial pulsations of a gas microbubble that is encapsulated by a thin viscoelastic shell and surrounded by an ideal incompressible liquid is carried out. Small axisymmetric disturbances in the microbubble shape are imposed and their long and short term stability is examined depending on the initial bubble radius, the shell properties, and the parameters, i.e., frequency and amplitude, of the external acoustic excitation. Owing to the anisotropy of the membrane that is forming the encapsulating shell, two different types of elastic energy are accounted for, namely, the membrane and bending energy per unit of initial area. They are used to describe the tensions that develop on the shell due to shell stretching and bending, respectively. In addition, two different constitutive laws are used in order to relate the tensions that develop on the membrane as a result of stretching, i.e., the Mooney-Rivlin law describing materials that soften as deformation increases and the Skalak law describing materials that harden as deformation increases. The limit for static buckling is obtained when the external overpressure exerted upon the membrane surpasses a critical value that depends on the membrane bending resistance. The stability equations describing the evolution of axisymmetric disturbances, in the presence of an external acoustic field, reveal that static buckling becomes relevant when the forcing frequency is much smaller than the resonance frequency of the microbubble, corresponding to the case of slow compression. The resonance frequencies for shape oscillations of the microbubble are also obtained as a function of the shell parameters. Floquet analysis shows that parametric instability, similar to the case of an oscillating free bubble, is possible for the case of a pulsating encapsulated microbubble leading to shape oscillations as a result of subharmonic or harmonic resonance. These effects take place for acoustic amplitude values that lie above a certain threshold but below those required for static buckling to occur. They are quite useful in providing estimates for the shell elasticity and bending resistance based on a frequency/amplitude sweep that monitors the onset of shape oscillations when the forcing frequency resonates with the radial pulsation, ? f =? 0 , or with a certain shape mode, ? f =2? n . An acceleration based instability, identified herein as dynamic buckling, is observed during the compression phase of the pulsation, evolving over a small number of periods of the forcing, when the amplitude of the acoustic excitation is further increased. It corresponds to the Rayleigh-Taylor instability observed for free bubbles, and has been observed with contrast agents as well, e.g., BR-14. Finally, phase diagrams for contrast agent BR-14 are constructed and juxtaposed with available experimental data, illustrating the relevance and range of the above instabilities. © 2011 American Institute of Physics.

    Related items

    Showing items related by title, author, creator and subject.

    • Simulations of insonated contrast agents: Saturation and transient break-up
      Tsigklifis, Konstantinos; Pelekasis, N. (2013)
      Under insonation contrast agents are known to perform nonlinear pulsations and deform statically, in the form of buckling, or dynamically via parametric mode excitation, and often exhibit jetting and break-up like bubbles ...
    • Stability and simulations of insonated contrast agents-effect of the constitutive law
      Pelekasis, N.; Efthimiu, K.; Tsigklifis, Konstantinos (2011)
      Under insonation contrast agents are known to exhibit dynamic patterns such as thresholding, compression only behavior, diffusion and deflation, shape deformation, buckling, jetting and break-up, not all of which can be ...
    • The measurement of underwater acoustic noise radiated by a vessel using the vessel's own towed array
      Duncan, Alexander John (2003)
      The work described in this thesis tested the feasibility of using a towed array of hydrophones to: 1. localise sources of underwater acoustic noise radiated by the towvessel, 2. determine the absolute amplitudes of these ...
    Advanced search

    Browse

    Communities & CollectionsIssue DateAuthorTitleSubjectDocument TypeThis CollectionIssue DateAuthorTitleSubjectDocument Type

    My Account

    Admin

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Follow Curtin

    • 
    • 
    • 
    • 
    • 

    CRICOS Provider Code: 00301JABN: 99 143 842 569TEQSA: PRV12158

    Copyright | Disclaimer | Privacy statement | Accessibility

    Curtin would like to pay respect to the Aboriginal and Torres Strait Islander members of our community by acknowledging the traditional owners of the land on which the Perth campus is located, the Whadjuk people of the Nyungar Nation; and on our Kalgoorlie campus, the Wongutha people of the North-Eastern Goldfields.