MRI: Acquisition of a Digital Particle Image Velocimetry System for Studying Fluid Flow Around Organismal, Robotic and Marine Structures

资金将用于购买数字粒子图像测速(DPIV)系统，该系统将使学生和研究人员能够使用高分辨率视频记录来可视化和量化机器人生物和海洋结构物周围的流体流动。DPIV是一种用于定量显示流体流动的实验技术。流体介质被播撒有中性浮力的反射颗粒，这些颗粒被一片激光照射。粒子的运动由垂直于激光薄片的摄像机记录下来。矢量场是通过评估连续图像中的粒子组之间的互相关来计算的。所要求的数字图像处理系统包括一个低速高分辨率摄像机(高达30帧/S，1648x1214像素，512MB板载内存，14位数码输出，7.4x7.4m像素，LaVision Imager Pro X2M带PCII帧抓取器)，一个高速高分辨率摄像机(全分辨率1000f/S，低分辨率高达60000 f/S，12位数字输出，2 GB板载内存，1024x1024像素，17x17微米像素，LaVision High SpeedStar 3GigE)，以及一台高重复频率激光器(30 mJ/脉冲@527 nm，1 KHz重复率，带集成制冷机)。相机镜头包括：50 mm F/1.8镜头、50 mm F/1.4镜头、可变倍率12倍变焦Navitar镜头和带显微适配器的特写变焦镜头。光学包括一个焦距在300-2000 mm之间的可调透镜，一个-10 mm的焦距透镜，以及一个-20 mm的带减反射涂层的焦距透镜。粒子是近中性浮力的、反射的、密度为15 mg/L的中空玻璃粒子。通过控制计算机管理的计时单元，相机与激光同步记录。一个独立的计算机系统运行每个摄像机系统(低速和高速)，每个系统都能够控制激光(四核处理器PC、2 GB RAM、250 GB硬盘、RW DVD、19英寸显示器、软件和摄像机接口、LaVision)。Davis v.7软件由二维PIV/PTV(粒子跟踪测速)处理例程组成，用于图像采集、处理和硬件控制。Davis软件可以计算速度矢量和流场的导数，以及流线、射流、漩涡和其他流体结构的可视化。流动结构的运动学是通过使用ProAnalyst软件进行数字化和二维结构设计而编辑的随时间变化的图像而得到的。在具体项目中进行的定量流动可视化将包括描述鱼鳍周围的流体流动，分析对浮游生物游泳和分布的平流影响，计算声纳部件的摩擦力和阻力，描述水下机器人和非稳定可再生能源设备上的流动分离，以及确定海洋环境中沉没表面上生物膜形成和生物污垢造成的阻力效应。在自然和工程系统中，流体流动的定量表征都是至关重要的，因为在这些系统中，流体的运动影响生物的形态、功能和生态，并决定对海洋结构物施加的力。所要求的系统旨在实现从微观到宏观长度范围内的各种流体流动状态的实验，并支持工程、生命科学和海洋学方面的研究。DPIV系统将使研究项目能够研究机器人、海洋结构、声纳组件和从细菌、浮游生物到鲨鱼的生物系统周围的流动。一个由URI、普罗维登斯学院和罗杰·威廉姆斯大学的生物学家、工程师和海洋学家组成的跨学科团队提出了一系列令人兴奋的研究项目，探讨了流体在以下方面的作用：(1)鱼翅周围的流体流动，(2)流体对胶状浮游动物推进和捕食相互作用的影响，(3)流体对浮游生物生态和分布的影响，(4)摩擦和阻力对SONR组件的摩擦学研究，5)海洋环境中微生物生长导致的阻力和能量损失，以及(6)用于水下机器人和可再生能源设备反馈控制的局部流动检测。收购DPIV系统提供了关键能力，增强了国际扶轮高等教育机构在研究和教育方面的竞争力。该系统将用于本科生和研究生课程，本科生和研究生以及博士后研究人员将接受培训，以便在他们的研究中使用DPIV系统。学生从这种实践学习方法中受益，这种方法依赖于以实际和直观的方式将基本科学学科与数学和分析方法相结合。

Funds will be used to purchase a digital particle image velocimetry (DPIV) system that will enable students and researchers to visualize and quantify fluid flow around robotic biological, and marine structures using high-resolution video recordings. DPIV is an experimental technique for quantitatively visualizing fluid flow. The fluid medium is seeded with neutrally buoyant, reflective particles that are illuminated by a sheet of laser light. Particle movement is recorded by a camera, oriented perpendicular to the laser sheet. Vector fields are calculated by evaluating the cross-correlation between groups of particles in successive images. The requested DPIV system consists of a low-speed high-resolution camera (up to 30 frames/s, 1648x1214 pixel resolution, 512 MB onboard memory, 14-bit digital output, 7.4x7.4 µm pixels, LaVision Imager Pro X2M with PCII Frame Grabber), one high-speed high-resolution camera (1000 f/s at full resolution, up to 60,000 f/s at reduced resolution, 12 bit digital output, 2GB onboard memory, 1024x1024 pixel resolution, 17x17µm pixels, LaVision HighSpeedStar 3 GigE), and a high repetition laser (30 mJ/pulse @527nm at 1 kHz repetition rate, with integrated chiller). Camera lenses include a: 50 mm F/1.8 lens, 50mm F/1.4 lens, variable magnification 12X zoom Navitar lens, and a close-up zoom lens with an adaptor for microscopic use. Optics include an adjustable lens with focal length between 300-2000 mm, one -10 mm, and one -20 mm focal length lens with anti-reflection coating. Particles are near neutrally buoyant, reflective, hollow glass particles at a density of 15 mg/l. A camera is synchronized to record simultaneously with the laser through a timing unit managed by a control computer. A separate computer system runs each of the camera systems (low- and high-speed) and each system is capable of controlling the laser (quad-core processor PC, 2 GB Ram, 250 GB hard drive, RW DVD, 19" monitor, software and camera interface, LaVision). DaVis v.7 software, consisting of processing routines for 2D PIV/PTV (Particle Tracking Velocimetry), is used for image acquisition, processing, and hardware control. DaVis software allows calculation of velocity vectors and derivatives of the flow field along with the visualization of streamlines, jets, vortices and other fluid structures. The kinematics of flow structures are derived by compiling the images over time using ProAnalyst software for digitizing and 2D structure design. Quantitative flow visualization performed in specific projects will include characterizing fluid flow around shark fins, analyzing advective effects on plankton swimming and distributions, calculating friction and drag forces on SONAR components, characterizing flow separation on underwater vehicles and unsteady renewable energy devices, and determining drag effects due to biofilm formation and biofouling onsurfaces submerged in marine environments.The quantitative characterization of fluid flows is of fundamental importance in both natural and engineered systems, where the motion of fluid affects the morphology, function and ecology of organisms and determines the forces exerted on marine structures. The requested system is designed to enable experiments ranging from microscopic to macroscopic length scales, in a range of fluid flow regimes and supports research in engineering, life sciences and oceanography. The DPIV system will enable research projects studying the flow around robotic, marine structures, sonar components and biological systems ranging from bacteria and plankton to sharks. An interdisciplinary team including biologists, engineers and oceanographers at URI, Providence College, and Roger Williams University proposed an exciting set of research projects that examine the role of fluid flow in (1) the fluid flow around shark fins, (2) fluid effects on propulsion and predator prey interactions of gelatinous zooplankton, (3) fluid effects on the ecology and distribution of planktonic organisms, (4) tribological studies of friction and drag on SONR components, 5) drag and energy loss due to microbial growth on surfaces submerged in marine environments, and (6) local flow detection for feedback control of underwater vehicles and renewable energy devices. Acquisition of the DPIV system provides critical capabilities that strengthen RI higher education institutions' competitiveness in research and education. The system will be used in undergraduate and graduate courses and both undergraduate and graduate students and postdoctoral researchers will be trained to use the DPIV system in their research. Students benefit from this hands-on learning approach that relies on integrating basic scientific disciplines with mathematical and analytical approaches in a practical and intuitive manner.