Nikhil Desai -- Self-propulsion of Marangoni-stress-driven active drops along a wall [ONLINE]
| Dates: | 8 May 2024 |
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| Times: | 13:00 - 14:00 |
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| What is it: | Seminar |
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| Organiser: | Department of Mathematics |
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| Who is it for: | University staff, External researchers, Current University students |
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| Speaker: | Nikhil Desai |
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Join us for this seminar by Nikhil Desai (Cambridge) as part of the North West Seminar Series in Mathematical Biology and Data Sciences
The talk will be hosted by the University of Liverpool and available to watch via zoom. Please contact carl.whitfield@manchester.ac.uk or mdomijan@liverpool.ac.uk for the link, or sign up to the mailing list.
Title: Self-propulsion of Marangoni-stress-driven active drops along a wall
Abstract: Active drops are synthetic, micron-sized swimmers that convert chemical energy into mechanical motion. These drops are physico-chemically isotropic and emit/absorb chemical solutes whose concentration gradients cause interfacial flows and stresses, which drive the solute's own transport via advection. This nonlinear coupling between fluid flow and solute transport around the drop causes a spontaneous symmetry-breaking, leading to self-propulsion of the drop, if the ratio of convective-to-diffusive solute transport, or Peclet number, is large enough. As a result of their net buoyancy, active drops generally evolve at small finite distances from boundaries. Yet, many theoretical studies on drop propulsion focus on unbounded domains, where problems are more tractable due to a simpler geometry. Using numerical simulations, we address this gap in understanding and provide physical insights on the spontaneous propulsion of active drops along a rigid wall. We first model the drop as a rigid sphere that emits a solute isotropically, and develops a surface 'slip velocity' in response to concentration gradients of this solute. We show that, and explain why, a reduction in the drop-to-wall separation actually promotes the self-propulsion of this model drop. We also consider viscous drops that swim due to surface flows (diffusiophoretic effects) as well as surface stresses (Marangoni effects), and show how the relative strengths of these two effects influences the drop's motion near a rigid wall.
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Speaker
Nikhil Desai
Role: PDRA
Organisation: University of Cambridge
Travel and Contact Information
