Cartwright Avriel, Du Jian
Department of Mathematical Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA.
Appl Sci (Basel). 2021 Oct;11(19). doi: 10.3390/app11199109. Epub 2021 Sep 30.
Microorganisms often swim within heterogeneous fluid media composed of multiple materials with very different properties. The swimming speed is greatly affected by the composition and rheology of the fluidic environment. In addition, biological locomotions are also strongly influenced by the presence of phase boundaries and free interfaces, across which physical properties of the fluid media may vary significantly. Using a two-fluid immersed boundary method, we investigate the classical Taylor's swimming sheet problem near interfaces within multi-fluid media. The accuracy of the methodology is illustrated through comparisons with analytical solutions. Our simulation results indicate that the interface dynamics and phase separation in the multi-fluid mixture are closely coupled with the movement of the swimmer. Depending on the interface location, the frictional coefficient, and the multi-fluid composition, the swimmer can move faster or slower than that in a single phase fluid.
微生物常常在由多种性质差异极大的材料构成的非均匀流体介质中游动。其游动速度会受到流体环境的组成和流变学的极大影响。此外，生物运动也会受到相界和自由界面的强烈影响，流体介质的物理性质可能会在这些界面处发生显著变化。我们采用双流体浸入边界法，研究了多流体介质中界面附近的经典泰勒游动薄片问题。通过与解析解的比较，说明了该方法的准确性。我们的模拟结果表明，多流体混合物中的界面动力学和相分离与游动者的运动紧密耦合。根据界面位置（原文此处有误，根据前文应是界面位置、摩擦系数和多流体组成），游动者在多流体中可能比在单相流体中移动得更快或更慢。
