Levich Institute Seminar – Tuesday, 09/13/2022

Tuesday, 09/13/2022
2:00 PM
Steinman Hall 124 (Exhibit Room)

Professor Hassan Masoud
Michigan Tech University Mechanical Engineering/Engineering Mechanics Department

“Design and Analysis of Marangoni Surfers”

Simultaneous Zoom Link: https://ccny.zoom.us/j/86074227655


We study the surfing motion of chemically-active objects along a flat liquid-gas interface. The objects are self-propelled by means of creating and maintaining a surface tension gradient resulting from an asymmetric release of a chemical agent. We use theory, numerical simulation, and experiments to examine the propulsion of these Marangoni surfers. First, we consider the behavior of simple surfers at a wide range of release rates and diffusivity of the exuded chemical species (that set the effective Reynolds and Peclet numbers), and subject to various degrees of confinement represented by the thickness of the liquid film. We show that the surfers can undergo a forward, backward, or an arrested motion, and identify the link between these modes of mobility and the flow structure in the vicinity of the surfers. We also find, perhaps surprisingly, that there exist certain intermediate Reynolds and Peclet numbers at which the propulsion speed of the surfers reaches a peak. Next, we focus on the dynamics of a self-powered and remotely controlled robot, which is inspired by water-walking insects and uses the Marangoni effect for both forward motion and change of direction. We analyze the performance of this surfing robot (characterized by its speed, fuel efficiency, and maneuverability) and showcase its novel capabilities. Overall, the findings of our investigations provide new insights into the propulsion of Marangoni-driven surfers and help establish engineering guidelines for their efficient design and effective operation.


Dr. Masoud joined the Department of Mechanical Engineering-Engineering Mechanics at Michigan Tech in July 2017 after a two-year stint at the University of Nevada, Reno. Prior to UNR, he was a lecturer at Princeton University and a post-doctoral fellow working jointly with Michael Shelley at the Courant Institute of Mathematical Sciences and Howard Stone at Princeton University. Dr. Masoud received his Ph.D. in Mechanical Engineering from Georgia Tech in 2012.
Interfacial and Multiphase Flows, Fluid-Structure Interaction, Flow Through Porous Media
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