COMPUTATION OF ACOUSTIC RADIATION AND INTERPARTICLE FORCES FOR SPHERES IN MICROFLUIDIC DEVICES

Abstract

In this thesis, the acoustic radiation and interparticle forces acting on micro spheres were studied theoretically by using the proposed numerical algorithms. The study was conducted for both cases of ideal and viscous fluid to investigate the effects of viscosity. The acoustic radiation force, also known as acoustic primary force, pushes rigid spheres towards the pressure node of a plane standing wave. We have concluded from the numerical results that, for a single sphere, the viscosity effect on the acoustic radiation force becomes larger as the radius of the sphere decreases. This was in agreement with the reported results in the literature. For the case of multiple spheres, we have described that the aggregation of spheres near the pressure node is due to the interparticle forces. Moreover, the interaction between the spheres is significantly stronger in viscous fluid due to the acoustic streaming.