Laboratory experiments on symmetric and asymmetric mode-2 internal solitary waves in a three-layer fluid

Magda Carr, Peter Davies, Ruud Hoebers

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    Numerous observational examples of Mode-2 internal solitary waves (ISWs) in the ocean (e.g. Yang et al.[12], Schroyer et al.[8]) have motivated recent modelling studies. The present laboratory investigation has been undertaken to investigate aspects of the behaviour of Mode-2 ISWs predicted by numerical model results obtained by Salloum et al. [6] and Olsthoorn et al.[5]; in particular, the dependence of the structure and stability of such waves upon asymmetrical initial conditions. As in the numerical models, asymmetry in the initial conditions is imposed by a prescribed offset between the mid-depth of the undisturbed 3-layer stratified fluid and the mid-level of the middle layer. For stable mode-2 waves, the experiments demonstrate that observed flow patterns (and their time development) agree well with numerical model predictions. For symmetrical initial conditions (0% offset), the amplitudes of the dominant and secondary mode-2 waves (and their phase velocities) are seen to agree well with the values obtained numerically by Olsthoorn et al [5] for identical conditions. The critical amplitude required for mode-2 ISW instability compares well with the predicted value for symmetrical initial conditions but the critical amplitude is shown to decrease for increasing degrees of asymmetry in the initial conditions. As the initial condition asymmetry (i.e the % offset) increases, the top-bottom asymmetry of the manifestation of instability is shown to increase.

    Original languageEnglish
    Title of host publicationProceedings of the 19th Australasian Fluid Mechanics Conference, AFMC 2014
    PublisherAustralasian Fluid Mechanics Society
    ISBN (Print)9780646596952
    Publication statusPublished - 2014
    Event19th Australasian Fluid Mechanics Conference - Melbourne, Australia
    Duration: 8 Dec 201411 Dec 2014

    Conference

    Conference19th Australasian Fluid Mechanics Conference
    Abbreviated titleAFMC 2014
    CountryAustralia
    CityMelbourne
    Period8/12/1411/12/14

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