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Boudina, Mouad

University of British Columbia

Surface tension in nature and engineering acts on elastic slender bodies of complex and nonuniform shapes. We study three fluid-structure interaction problems at the capillary scale in linearly diverging channels as a simplest geometrical nonuniformity, and highlight outcomes of coupling elasticity and geometry. In the first problem we investigate the dynamics of capillary wicking. We show that a diverging flexible channel prevents occlusion and, unlike a rigid one, speeds up the flow compared to a straight channel, hence serves as a potential cheap and convenient component in microfluidic circuits. The second problem solves the equilibrium states of a liquid bridge between nonparallel sheets in the context of stiction in micro-scale devices. We find multiple solutions for given liquid volumes and identify a hysteresis effect, as well as an isola center so far unreported in elastocapillary problems. Unlike rigid walls, the bridge remains sustained away from the ends even if the liquid is totally wetting, and the channel stays open upon slow volume variation. We analyse in the third problem the motion of a sliding drop between a pair of elastically hinged plates and the role of rest angles and initial conditions in delaying closure. We then examine the collective bundling of multiple side-by-side plates, an example of an unstable homogeneous medium where a disturbance amplifies while traveling in a constant speed and leaves a pattern of clusters.

Text

2024-12-20

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/89972

Mechanical Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/