Element Modeling – FEMLAB – Fluid Scattering –

Abstract Analytical solutions to the problem of wave scattering from three dimensional structures such as spheres have been studied extensively in the past. However, these solutions are not flexible enough to be extended to wave scattering from complex geometries. We have developed a finite element model of acoustic wave propagation through spherical structures to solve the problem of high-frequency (20 – 60 MHz) acoustic scattering. The long term goal of this research is to understand the interaction of ultrasound with micrometer sized objects such as cells. The FEMLAB ® software package (COMSOL AB, Stockholm) was used to solve the computational model, whereas MATLAB ® (Mathworks, Inc., Natick, MA) was used to calculate the analytical solutions. The computational model was verified against analytical solutions of near-field frequency-domain scattering of a high frequency acoustic plane wave incident by fluid, rigid and elastic spherical homogenous objects immersed in water. Overall maximum and average errors of ~12 % and ~5%, respectively were found between the analytical (Faran or Anderson theory, depending on whether and elastic or fluid sphere were modeled) and finite-element solutions of the pressure field distribution surrounding the spheres. Applications of these models in the biomedical field, such as high frequency ultrasound scattering from cells, are also presented