Deformable bodies in anisotropic fluids: from activity to elasticity

Thomas Chandler Cambridge Fluids Network - fluids-related seminars 27 June 2024 1:00pm MR14, Centre for Mathematical Sciences, Wilberforce Road, Cambridge Fluid anisotropy, or a direction-dependent response to deformation, can be observed in biofluids like mucus or, at a larger scale, self-aligning swarms of bacteria. A model fluid used to investigate such environments is a nematic liquid crystal. Large colloidal particles undergo shape-dependent interactions when immersed in these complex environments, whilst deformable bodies (like red blood cells) tend to be stretched, offering a passive means of measuring cell material properties. Adding to the complexity are microorganisms that propel themselves through these environments, which give rise to active stresses and topological defects, which focus elastic stresses and are important sites in many biological settings. In this presentation, we use complex variables to analytically solve for the interaction between bodies immersed in an active liquid crystal. This approach allows for the analytical solutions of a wide range of problems, opening the door to studying the role of body geometry, liquid crystal anchoring conditions, topological defects, and activity. Shape-dependent forces between bodies, local surface tractions, active stresses, and body deformation will also be discussed.