Title: Snap, Jump, and Wiggle: Motion in Micellar Fluids
Speaker: Andrew Belmonte
Speaker Info: Penn State U.
Non-Newtonian or viscoelastic fluids do many things which Newtonian fluids cannot do. Examples include rod climbing, the tubeless siphon, and cusp-like tails on rising bubbles. In this talk I will describe the even more peculiar behavior of aqueous micellar solutions in which the micelles take the form of long tubes (often called wormlike micelles). Our approach is both experimental and mathematical. By way of introduction to non-Newtonian fluid dynamics, I will present results on the spin down of a micellar fluid. I will then discuss new observations of the oscillations of bubbles (and spheres) rising (and falling) in a wormlike micellar fluid. We model these phenomena with various constitutive relations, and in particular focus on an ordinary differential equation model for the falling sphere in an infinite medium. For a Newtonian sphere this model is exact, for which we have proven that the sphere cannot oscillate. The work presented is in collaboration with Anand Jayaraman, Jon Jacobsen, and Andrea Young.Date: Friday, June 9, 2000