UNS:Collaborative Research: Multiscale interactions between active particles and stratified fluids during collective vertical migration

UNS：合作研究：集体垂直迁移过程中活性颗粒与分层流体之间的多尺度相互作用

• 批准号: 1510615
• 负责人: Eckart Meiburg
• 金额: $ 20万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-15 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1510615&HistoricalAwards=false
• 关键词: UNS; Collaborative; Research; Multiscale; interactions

CBET - 1510607/1510615PI: Dabiri, John/Meiburg, EckartThis collaborative project uses experiments and numerical simulation to investigate the collective motion of small swimming organisms in water. The hypothesis underlying the project is that the collective motion of many small organisms can induce fluid motion over length scales that are much larger than the organism itself. The investigators will focus on motion in stratified fluid layers, which are commonly found in the ocean, where the top fluid layer usually is warmer and saltier than deeper fluid layers. The stratification can lead to an instability that induces fluid motion, but the presence of the swimming organisms may change conditions for the onset of the motion and affect detailed flow patterns and fluid mixing that result from the motion. Although the research focuses on motion in the ocean as an example, the insights gained from the project will apply to other particulate and multiphase systems. Both investigators will involve high school students, undergraduates and graduate students in the project. Results from the project will be used in outreach efforts to engage in the research students from groups that are traditionally underrepresented in science and engineering.The objective of the proposal is to address experimentally and numerically the fundamental questions of multi-scale, many-body, fluid-structure interactions in stratified layers. The experiments will use a unique system that can produce on-demand vertical migrations of plankton via phototaxis in a controlled laboratory setting. A laser-guidance system will control swimming speed and swimmer spacing in collective motions. Two-dimensional particle imaging velocimetry will be used to measure flows generated by the swimmers' motion. The numerical methods implemented in the project are capable of simulating large numbers of swimming organisms with fidelity sufficient for studying details of both the near- and far-field flows. Numerical simulations will help test the possibility that collective swimming motions drive large-scale convection by modifying effective diffusivities of heat and salinity so as to induce double-diffusive convection.

CBET -1510607/1510615PI：Dabiri，John/Meiburg，Eckartthis合作项目使用实验和数值模拟来研究水中小型游泳生物的集体运动。该项目的基础假设是，许多小生物的集体运动可以在长度尺度上诱导流体运动，而长度比生物本身大得多。 研究人员将专注于分层流体层的运动，这些层通常在海洋中发现，在海洋中，顶部流体层通常比更深的流体层更温暖和盐。 分层会导致诱导流体运动的不稳定性，但是游泳生物的存在可能会改变运动发作的条件，并影响详细的流动模式和由运动导致的流体混合。 尽管该研究以海洋运动为例，但从项目中获得的见解将适用于其他颗粒和多相系统。 两位调查人员将参与该项目的高中生，大学生和研究生。 该项目的结果将用于推广工作，以参与科学和工程中传统上代表性不足的小组的研究学生。该提案的目的是在实验和数字上解决多种规模，多体，多体，多体，多体，多体，多体，多体，多体，多体，多体，多体，多体，多体，多体，，多体，多体，多体，多体，多体，多，，多体，多体，多体，多体，多，分层层中的流体结构相互作用。 实验将使用一个独特的系统，该系统可以在受控的实验室环境中通过光的点播垂直迁移。 激光指导系统将控制游泳速度和集体运动的游泳器间距。 二维粒子成像速度法将用于测量游泳者运动产生的流动。 该项目中实施的数值方法能够模拟大量的游泳生物，其富裕性足以研究近场和远场流的细节。 数值模拟将有助于测试集体游泳运动通过修改有效的热和盐度扩散以引起双向对流的有效扩散的可能性。