Acoustic streaming induced in focused Gaussian beams

摘要: Axisymmetric flow equations for a viscous incompressible fluid are transformed into the vorticity transport and Poisson’s equations. They numerically solved via finite difference method imposing appropriate initial boundary conditions. A model source of 1‐cm radius 5‐cm focal length with Gaussian amplitude distribution radiates 5‐MHz ultrasound beams in water. Numerical examples shown buildup acoustic streaming along across axis. Evidently, hydrodynamic nonlinearity has an essential effect on generation comparison linear case; reduces velocity prefocal region, whereas it tends to accelerate postfocal region.