Feedback control of falling liquid films


The event is taking part on the Tuesday, May 16th 2017 at 15.30
Theme/s: Pure and Applied Colloquia
Location of Event: Alan Turing 306
This event is a: Public Seminar

Abstract: The flow of a fluid layer with one interface exposed to the air and the other an inclined planar wall becomes unstable due to inertial effects when the fluid layer is sufficiently thick or the slope sufficiently steep. This free surface flow of a single fluid layer has industrial applications including coating and heat transfer, which benefit from smooth and wavy interfaces respectively. I will discuss how the instabilities of the system can be modified and controlled by introducing either pre-determined patterning, or altering system properties in real time in response to observations of the interface state. This feedback could be delivered by injection and withdrawal of fluid into the system, which has a very direct effect on the dynamics, or through localised heating of the wall bounding the substrate. Heat is then conducted and advected through the system, and eventually affects the interface dynamics through temperature-dependent surface tension. In either case, we find that real time feedback control is remarkable effective, even when combined with realistic restrictions on observations and actuation.
Furthermore, the controls can be used to drive the system towards arbitrary steady states and travelling waves, and the qualitative effects are independent of the details of the flow modelling.

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External Speakers

Alice Thompson (University of Manchester)