A computational parameter study for three-dimensional shock-bubble interactions.

摘要

The morphology of the multifluid compressible flow associated with a shock-bubble interaction in a gas environment is characterized using a series of three-dimensional multifluid Eulerian simulations. The bubble consists of a spherical gas volume of radius 2.54 cm (128 grid points) which is accelerated by a planar shock wave. Fourteen scenarios are considered: four gas combinations, including Mach numbers 1.1M≤5 and Atwood numbers -0.8A0. The data are queried at closely-spaced time intervals in order to characterize the temporal evolution of various integral features of shock-bubble interactions, including the mean density, internal energy, mean velocity, dimensions, and circulation associated with the shocked bubble. Scaling arguments based on quantities computed from one-dimensional gas-dynamics are found to collapse the trends in many of these quantities successfully for fixed A, although complex changes in the shock wave refraction pattern introduce effects that preclude successful scaling across the gas combinations.; An azimuthal averaging scheme is implemented in order to extract mean and fluctuating density and enstrophy fields, from which the intensity, spatial distribution, and spectral content of these fluctuations are computed for each of the scenarios. The data indicate that a transient turbulent state is achieved only for convergent geometry and A>0.2. The action of nonlinear-acoustic effects and vorticity generation is depicted in sequenced visualizations of the density and vorticity fields, and of the azimuthal mean and fluctuating density and enstrophy fields. Effects associated with the inclusion of a thin, dense, film-like cladding on the interface are quantified using an additional series of simulations, showing that the effects are insignificant except in cases with |A|0.2.