An extended Rayleigh model of bubble evolution

An extended Rayleigh model for laser generated bubbles in water and soft ti ssue is presented. This model includes surface tension, viscosity, a realis tic equation of state, material strength and failure, stress wave emission, and linear growth of interface instabilities. The model is validated by co mparison to detailed compressible hydrodynamic simulations using the LATIS computer program. The purpose of this study is to investigate the use of th e extended Rayleigh model as a much faster and simpler substitute for the d etailed hydrodynamic simulations when only limited information is needed. I t is also meant to benchmark the hydrosimulations and highlight the relevan t physics. The extended Rayleigh model and the hydrosimulations are compare d using both a 1D spherical geometry with a bubble in the center and a 2D c ylindrical geometry of a laser fiber immersed in water with a bubble formed at the end of the fiber. Studies are done to test the validity of the mate rial strength and failure, stress wave emission, and the interface instabil ity terms in the extended Rayleigh model. The resulting bubble radii, mater ial damage radii, the emitted stress wave energies, and the size of the int erface distortions are compared. Many of the trends found in the hydrosimul ations are illuminated by the extended Rayleigh model owing to its relative simplicity. The extended Rayleigh model is very useful since it is accurat e over a large range of parameters and it is computationally much faster th an the hydrosimulations. (C) 2001 American Institute of Physics.