|Institution:||University of Birmingham|
|Full text PDF:||http://etheses.bham.ac.uk/5986/|
In this thesis a numerical method is developed for modelling multiple bubbles with axis-symmetric geometry, in a domain of three ﬂuids separated by two ﬂuid-ﬂuid interfaces. The density ratios across these interfaces can vary allowing simulations of bubble inter-action with rigid boundaries, free surfaces and any density ratio values between these two extremes. The inclusion of buoyancy and surface tension into the simulations allow for a wide array of possible models, including investigations into explosion bubbles and biomedical applications. The evolution of the bubble is analysed in various scenarios right through to the toroidal stage of bubble collapse. The numerical simulations are conducted using the boundary integral method with vortex ring calculations for modelling the bubble transition from the simply connected bubble to the doubly connected toroidal phase. The numerical method is then compared with numerical and experimental data from other work to verify the validity of the model. The results show good agreement with past numerical results for spherical bubble oscillations and rigid boundary collapse. The veriﬁed model is then used to simulate a multitude of scenarios to investigate two bubble interaction with applications to mixing. A range of parameters are investigated and results are given for an optimal mixing approach. The introduction of a curved density interface is explored to determine the eﬀect it has on bubble collapse. The curved interface collapse is then adapted to consider bubble collapse near a cell wall.