Mathematical Scienaes: Computational Modeling of Swimming Organisms

数学科学：游泳生物的计算模型

• 批准号: 9501048
• 负责人: Lisa Fauci
• 金额: $ 9万
• 依托单位: Tulane University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-01 至 1999-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9501048&HistoricalAwards=false
• 关键词: Mathematical; Scienaes; Computational; Modeling; Swimming

Fauci The investigator develops and implements computational methods for modeling the fluid dynamics problems of aquatic animal locomotion across a wide range of animal sizes. Of interest are both the dynamics of a single organism and the relationship of its morphology to its motility properties, and the collective hydrodynamic interactions of groups of swimmers with each other and their environment. Applications studied include bacterial chemotaxis in micropores, spermatozoa motility in the reproductive tract, and the coupling of active and passive tissue properties to the external swimming mechanics of a leech. Bacterial chemotaxis in micropores is of special interest, because the transport behavior of microorganisms through porous media is important in studying the contamination of groundwater supplies. Although bioremediation, the process by which microbes degrade contaminants, has field scale implications, the detailed study of pore-level behavior of the coupled fluid-contaminant-microbial system is essential. The project's computational model includes the detailed analysis of hydrodynamics, contaminant reaction, diffusion and convection, and the chemotactic responses of the swimming microbes. This allows the systematic study of the influence of different parameters, such as swimming speed, diffusion rates, microbial uptake rates, as well as stochastic parameters relating to the likelihood with which microbes change their swimming direction in response to the evolving contaminant field. This is difficult, if not impossible, to examine in a laboratory environment. The project studies the way organisms swim, using computational models. The organisms studied vary in size from bacteria to leeches. Of paramount importance in the study of bacterial transport in micropores is the growth of biofilms. Under certain physical and chemical conditions, microbes adhere to each other and the local pore structure. This biofilm growth affects and is affe cted by the local flow characteristics and contaminant transport. The computational model has the ability to model complex, dynamic fluid-structure interactions. Agglomeration is modeled by exerting appropriate binding stresses between discrete representations of organisms, that may hold them together, or, if fluid stresses are large, may yield and release the organisms. The model is a powerful tool for understanding biofilm processes at a micropore level. This has important consequences for environmental problems.

研究人员开发并实现了计算方法，用于模拟水生动物运动的流体动力学问题，这些问题涉及各种动物的大小。感兴趣的是单个生物体的动力学及其形态与运动特性的关系，以及游泳者群体彼此之间及其环境的集体流体动力学相互作用。研究的应用包括微孔中的细菌趋化性，生殖道中的精子运动，以及主动和被动组织特性与水蛭外部游泳力学的耦合。细菌在微孔中的趋化性引起了特别的兴趣，因为微生物通过多孔介质的运输行为对研究地下水供应的污染很重要。虽然生物修复（微生物降解污染物的过程）具有现场规模意义，但对耦合流体-污染物-微生物系统的孔隙级行为的详细研究是必不可少的。该项目的计算模型包括对流体动力学、污染物反应、扩散和对流以及游动微生物的趋化反应的详细分析。这样就可以系统地研究不同参数的影响，如游泳速度、扩散速率、微生物摄取速率，以及与微生物根据不断变化的污染物场改变其游泳方向的可能性有关的随机参数。这在实验室环境中很难检验，如果不是不可能的话。该项目利用计算模型研究生物的游泳方式。被研究的生物从细菌到水蛭大小不一。在研究细菌在微孔中的运输中，生物膜的生长是最重要的。在一定的物理和化学条件下，微生物相互粘附并形成局部的孔隙结构。这种生物膜的生长影响并受局部流动特性和污染物输送的影响。计算模型能够模拟复杂的、动态的流固相互作用。通过在生物体的离散表示之间施加适当的结合应力来模拟团聚，这种结合应力可能使它们结合在一起，或者，如果流体应力很大，可能使生物体屈服并释放。该模型是在微孔水平上理解生物膜过程的有力工具。这对环境问题有重要影响。