MechE MS Thesis Defense: Jesse Batson


ABSTRACT: The acoustic radiation force, as seen in apparatuses such as in an acoustic levitator, continues to find applications in materials science, manufacturing, and medical fields. One example ofthe utilization of an acoustic levitator is measuring the progress of clotting blood droplets. One of the largest advantages of using acoustic levitation is that the process is a minimal contact method. In some biological and chemical processes, surface contact can corrupt measurements,and acoustic levitation avoids these issues by using the acoustic radiation force to contain andmanipulate the blood drop. The deformation of Newtonian liquid droplets via acoustic levitation has been well studied. In that case, the shape of the droplet is governed by the surfacetension and shape curvature (Young-Laplace equilibrium). The quasi-static deformation of elastic droplets in acoustic levitators, however, has not yet been investigated. In this thesis, weexplore the application of acoustic levitation to the characterization of the deformation of softelastic droplets.

This thesis consists of three main efforts. To start, the history of the acoustic radiationforce and the impacts they have made are discussed. These studies however, deal with dropletsmuch smaller than the acoustic wavelength, such that the scattered components may be greatlysimplifed, thus simplifying the whole system. Next, a generalized theory for the acoustic radiation pressure acting on droplets of sizes similar to the length scale of the acoustic wavelength isdeveloped. We model the droplet as an incompressible, isotropic, linear elastic solid undergoingsmall deformations, under the conditions that the deformation is axisymmetric, with a purelyradial traction condition, where the traction condition is derived from the acoustic radiationpressure. The displacement and stress within the droplet is then solved for utilizing two potentials developed by Love (1926). We finish off by testing the validity of the theory by measuringthe deformation and location of soft alginate gels with known material properties in an acousticlevitator.

COMMITTEE: Advisor R. Glynn Holt, ME; Co-advisor Paul Barbone, ME/MSE; Raymond Nagem, ME

When 9:00 am to 12:00 pm on Monday, July 29, 2019
Location 110 Cummington Mall, Room 410