Inferring elastic moduli of drops in acoustic fields

Abstract

Acoustically levitated drops serve as non-contact mini-laboratories from which one can infer material properties from the response of the drop to the acoustic radiation force. Oddly enough, the oscillatory problem is more well-developed than the static problem. Analysis of the static acoustic deformation of Newtonian liquid drops is well established, yielding the inference of the surface tension. But the static deformation of an elastic drop is less well studied. The present work aims to enable the inference of elastic moduli from static deformations of acoustically levitated drops. The drop will be modeled as an incompressible, linear elastic solid undergoing small axisymmetric deformations. The axisymmetric interior stress and displacement fields will be found using Love's strain potential. The traction boundary condition can be calculated using linear acoustic theory . The measured static deformation of experimentally levitated drops with known material properties (polymer and protein gels) will be compared to the predictions of the theory. Time permitting, a finite element computational model will also be employed for comparison.Acoustically levitated drops serve as non-contact mini-laboratories from which one can infer material properties from the response of the drop to the acoustic radiation force. Oddly enough, the oscillatory problem is more well-developed than the static problem. Analysis of the static acoustic deformation of Newtonian liquid drops is well established, yielding the inference of the surface tension. But the static deformation of an elastic drop is less well studied. The present work aims to enable the inference of elastic moduli from static deformations of acoustically levitated drops. The drop will be modeled as an incompressible, linear elastic solid undergoing small axisymmetric deformations. The axisymmetric interior stress and displacement fields will be found using Love's strain potential. The traction boundary condition can be calculated using linear acoustic theory . The measured static deformation of experimentally levitated drops with known material properties (polymer and protein gels) will be com...