Endowed Distinguished Lecture Series in Fluid Mechanics
March 18, 2019 @ 4:05 pm - 5:00 pm
Howard A. Stone, Ph.D.
Donald R. Dixon ’69 and Elizabeth W. Dixon Professor
Seeking Intersections Between Disciplines: “Boundaries” in Multiphase Flows
Abstract: In this presentation I will discuss various multiphase flow problems that we have studied in recent years. These problems have often appeared when working with colleagues in different disciplines. New questions were generated but then were realized to have some relation to classical multiphase flow problems in fluid mechanics. Thus, I will discuss: (i) The “Bretherton” problem concerns a long bubble translating in a close-fitting, liquid-filled tube. We show via experiments and theory that, for the case of a bidisperse suspension, a bubble, which is separated from the wall by a thin film, acts as a speed-dependent filter to separate the small and large particles. (ii) A spherical particle translating at low Reynolds numbers (slow flows) parallel to a rigid wall maintains the same separation distance during its motion. We show using theory and experiments that a particle moving along an elastic membrane, which can deform by bending, is repelled from the membrane due to hydroelastic forces. (iii) It is well known that mechanics plays an important role in biological systems. I highlight a few cases of this interplay between mechanics and bacterial systems. At the heart of each of the problems mentioned above are classical ideas in mechanics.