Discrete multi physic model for the Rayleigh collapse of a single cavity

Albano, Andrea ORCID: 0000-0003-0998-1039 (2021). Discrete multi physic model for the Rayleigh collapse of a single cavity. University of Birmingham. Ph.D.

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Abstract

In this thesis, a Discrete Multi-Physics model based on Smoothed Particle Hydrodynamics is developed to simulate a Rayleigh collapse of a single bubble. All the simulations were run on a modified version of the open source software LAMMPS and visualised on OVITO. Initially a 2D model is validated by simulating a phenomenon that shares many similarities with a collapse mechanism, the interaction of a shock wave with a discrete gas inhomogeneity, showing similar performance to classic mesh based CFD. The model is then used to simulate a 2D Rayleigh collapse and validated against the 2D Rayleigh-Plesset equation for both empty and gas filled cavity. The validated model is used to investigate the role of heat diffusion at the gas-liquid interface of the cavity, and to study non-symmetrical collapse induced by the presence of a nearby surface. Enabling heat diffusion at the gas-liquid interface allowed to identify five different possible behaviours that range from isothermal to adiabatic, while the results of non symmetric collapse show that the surface is hit by a stronger shock when distance between the center of the cavity and the surface is zero while showing more complex double peaks behaviour for other distances. In the final chapter a 3D model is used to model an attached non-symmetrical collapse and its hydrodynamic is compared with the equivalent 2D case.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):