Collaborative Research: MSPA-MCS: Simulation and Visualization of Flow at Interfaces

界面流动的模拟与可视化摘要流体动力学中的许多重要现象都涉及到两个流体区域之间边界的变化。这些流体现象包括两种流体流动中的不稳定性，透明和含颗粒液体之间边界的演变，以及空气和水之间边界的行为。这项研究使用计算机模拟来研究流体之间的这种界面，以及从这些模拟中创建图像的新方法，以使研究人员能够更好地了解流体的行为。对流动界面进行更好的模拟和可视化，将促进对流动界面的科学认识，有助于工程设计。更广泛的影响领域包括用于医药的自行式微型机械的设计、河流表面运输的污染分析和控制，以及喷墨打印机的液滴形成控制。该项目还通过培训学生、聘请少数族裔学生参加暑期实习、为研究社区开发可视化流体模拟课程以及在网上发布代码和数据来推进教育。这项研究从修改几种不同类别的界面流动的现有数值模拟代码开始。本研究模拟和描绘的具体科学现象包括：富含颗粒物的区域沉积成透明流体时的不稳定性，包括类似Rayleigh-Taylor不稳定性；由于接触线上的表面张力效应，流体辫子和其他结构的发展；固体颗粒从淡水/盐水界面落下的内部飞溅；简单铰接人物的运动和在粘性流体中游泳的其他微型和纳米尺度机构。使用来自模拟的数据，利用各种技术(包括从颗粒创建表面、识别和跟踪3D流动中的临界点、流线布置以及模拟流变学流体悬浮液的各向异性照明)，为每种现象量身定做在界面上可视化流动的新方法。

Simulation and Visualization of Flow at InterfacesAbstractA wide variety of important phenomena in fluid dynamics involve the changes of the boundary between two fluid regions. Such fluid phenomena include the instabilities in two-fluid flows, the evolution of the boundary between clear and particle-laden liquids, and the behavior of the boundary between air and water. This research uses computer simulations to study such interfaces between fluids together with new methods of creating images from these simulations in order to allow researchers to gain a better understanding of the fluid behaviors. Better simulation and visualization of flow interfaces will advance scientific understanding and aid in engineering design. Areas of broader impact include the design of self-propelled micromachines for medicine, surface-transported pollution analysis and control on rivers, and controlling droplet formation for ink-jet printers. This project is also advancing education by training student, hiring minority students for summer internships, developing courses on visualizing fluid simulations for the research community, and distributing code and data on the web.This research begins with the modification of existing numerical simulation codes for several different classes of interfacial flows. The specific scientific phenomena that are simulated and visualized in this research includes: instabilities in the sedimentation of particle-laden regions into clear fluids, including the analogue of the Rayleigh-Taylor instability; the development of fluid braids and other structures due to surface tension effects at contact lines; the internal splashes of solid particles falling through fresh/salt-water interfaces; and locomotion of simple articulated figures and other micro- and nano-scale mechanisms for swimming through viscous fluid. Using the data from the simulations, new methods of visualizing the flow at interfaces are tailored to each phenomena utilizing various techniques including surface creation from particles, identification and tracking of critical points in 3D flows, streamline placement, and anisotropic lighting for simulated rheoscopic fluid suspensions.