Numerical investigation of the nonlinear dynamics of interacting microbubbles

Abstract

The successful application of MBs requires detailed understanding of the nonlinear behavior of microbubbles (MBs), especially in polydisperse clouds, where the dynamic of every individual MB affects the other MBs. However, there is not enough information on how the nonlinear oscillations of one MB influences the other and vice versa. In this work the dynamics of 2 and 3 interacting MBs of initial radii of 1μm<R0<4 μm are studied by investigating the pressure dependent resonance curves and the bifurcation diagrams of the MBs (1 MHz<f<15 MHz, 1 kPa<p<1 MPa) for cases of no interaction and interaction with varying MB-MB distances. Results show that, for small enough distances, the pressure dependent resonance frequencies (fr) and the pressure threshold for harmonic and SH fr decreases. The larger MB may force new peaks in the resonance curves of the smaller MB at fr, harmonic fr and SH fr of the larger MB. The larger MB can control the dynamics of the smaller MB and force the smaller MB to exhibit the same nonlinear behavior (e.g., ½, 1/3, 1/4 SH) as of the larger MB. The dynamics of a cloud of interacting MBs maybe controlled by controlling the dynamics of the larger MB in the population.