| Yhteenveto: | In this thesis, we explore different topics in the broad field of microscale swimming, focussing on microswimmers that propel themselves via slender appendages known as flagella. There is a wealth of biological examples, including helically driven bacteria, such as E. coli, and the well known and well studied human spermatozoon. Commensurate with this variety of examples from which microswimmer study draws inspiration and motivation, potential applications of developed understanding of this microscale world are also broad, spanning industry and medicine, particularly with the recent advent of synthetic microswimmers.
Driven by open questions in both biology and the theory of swimming at low Reynolds number, we investigate the behaviours of two flagellated organisms, one canonical and one lesser studied, in a range of computationally simulated microenvironments, from confined to multiswimmer settings. We form approximate dynamical systems for each of these model scenarios, averaging over the relatively short period of the flagellar beat, enabling thorough analysis of the dynamics via the resulting phase planes. Fundamental to these studies is knowledge of the motion of the flagellum, which we seek out from experimental data for the swimmer Leishmania mexicana, though we later relax this assumption of kinematic knowledge and move to consider the so-called elastohydrodynamic problem, in which fluid dynamics and elasticity can reshape the flagellar beat. We look towards realising systematic improvements to the accuracy of modern elastohydrodynamic techniques and, further, significantly broaden the scope of recent efficient methodologies to address the three-dimensional motion of slender elastic bodies in viscous fluid.
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