Coupling Internal and External Mechanics of Swimming Organisms: A Computational Approach

这个项目涉及水生动物运动的流体动力学，这个领域包括鞭毛运动和无脊椎动物游泳的研究。研究者和她的同事们探索了有机体的内力产生机制与外部粘性、不可压缩流体的耦合。一种统一的计算方法可以用来模拟纤毛的内部轴突机制，螺旋体的内部鞭毛产生力，以及水蛭游动机制的主动和被动组织特性的耦合。除了对单个生物体的动力学建模之外，还可以检查生物体群体及其环境的集体流体动力学相互作用。研究者建立了一个数学模型，用于研究由流体和被淹生物组成的耦合力学系统。所采用的数值方法是浸入边界法。完全可压缩的Navier-Stokes方程在一个域流体中求解，在这个域流体中，中性浮力生物经历了随时间的运动。这种方法的显著特点是，悬浮的有机体被流体动力学方程中力密度项的适当贡献所取代。这个跨学科项目采用现代科学计算方法来研究重要的生物过程。了解细菌的运动和聚集在生物修复中是至关重要的，生物修复是利用细菌降解有毒化学物质的过程。此外，纤毛、鞭毛和螺旋体的内部机制的研究在医学和生物技术方面也有应用。在这个项目中开发的计算算法将有助于研究其他生物流体动力学问题，并有助于高性能计算的专业知识。

Fauci9805492 This project concerns the fluid dynamics of aquatic animallocomotion, a field that encompasses the study of flagellarmotility as well as invertebrate swimming. The investigator andher colleages explore the coupling of the internalforce-generating mechanisms of the organisms with an externalviscous, incompressible fluid. A unified computational approachcan be adapted to model the internal axoneme mechanics of abeating cilium, the force-generating internal flagella ofspirochetes, as well as the coupling of active and passive tissueproperties to the swimming mechanics of a leech. In addition tomodeling the dynamics of a single organism, the collectivehydrodynamic interactions of groups of organisms and theirenvironment can be examined. The investigator has developed amathematical model designed to study the coupled mechanicalsystem comprised of the fluid and the immersed organism. Thenumerical method used is the immersed boundary method. The fullincompressible Navier-Stokes equations are solved in a domain offluid within which neutrally-buoyant organisms undergoingtime-dependent movements are immersed. The salient feature ofthis method is that the suspended organism is replaced bysuitable contributions to a force density term in the fluiddynamics equations. This interdisciplinary project employs modern methods inscientific computing to study important biological processes. Theunderstanding of bacterial motility and aggregation is of vitalimportance in bioremediation, the process by which bacteria areused to degrade toxic chemicals. In addition, the study of theinternal mechanisms of cilia, flagella and spirochetes hasapplications in medicine and biotechnology. The computationalalgorithms developed in this project will be useful in studyingother biofluiddynamic problems as well as contributing toexpertise in high performance computing.