Development and Deployment of a Versatile In Situ Underwater Miniature PIV System (UWMPIV)

多功能原位水下微型 PIV 系统 (UWMPIV) 的开发和部署

• 批准号: 0826477
• 负责人: Qian Liao
• 金额: $ 37.24万
• 依托单位: University of Wisconsin-Milwaukee
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0826477&HistoricalAwards=false
• 关键词: Development; Deployment; Versatile; Situ; Underwater

Particle Image Velocimetry (PIV) is an ideal technique to characterize turbulent flow structures at smaller scales, such as the dissipation rate of turbulent kinetic energy (TKE), rate of strain, and vorticities. It is, however, difficult to be adapted to field studies due to the requirement of high power lasers, high performance CCD cameras and full-fledged image acquisition computer systems, which are not suitable for submersible configurations. The PI's propose an alternative solution by using a class IIIb Diode Pumped Solid State (DPSS) laser which is powered by batteries. A light sheet is created by steering the continuous-wave laser beam through a rotating mirror, thus ensuring adequate light energy for illuminating small particles (~10 mm to ~100 mm) in natural waters while at the same time keep the exposure time of particle short to avoid blurred images. A preliminary system has been built with an ultra-mobile computer and a USB-based signal generator. The PI?s propose to improve the prototype UWMPIV system, so it can measure flows with higher speed and turbulence level and can adapt its orientation with shifting mean flow direction to avoid measurement error induced by out-of-plane motions. The improved system will be compact, versatile and allow for long-term observations (several days). The UWMPIV will be set up as a free-floating system that measures the vertical profiles of small-scale turbulence structures, including the dissipation rate, enstrophy and surface divergence immediately below the air-water interface. The purpose is to provide understanding of free surface turbulence and its effects on gas transfer through the air-water interface. Broader Impacts:The PIs do a very good job of outlining how this compact in-situ PIV system will be used in education and public outreach. As well as being used for labs and case studies in various civil engineering courses, the proposal has money for two graduate students. The collaboration with Discovery World at Pier Wisconsin sounds like an excellent opportunity to reach the public. PIV could provide a very different perspective of ocean flows, as it resolves 2D fields with exceptional detail. This is very seldom achieved with typical ocean observations, which are generally sparse.

粒子图像测速（PIV）是表征小尺度湍流结构的理想技术，如湍流动能耗散率（TKE）、应变率和涡度。然而，由于高功率激光器、高性能CCD相机和成熟的图像采集计算机系统的要求，难以适应现场研究，而这些都不适合潜水配置。PI提出了另一种解决方案，即使用由电池供电的IIIb级二极管泵浦固体（DPSS）激光器。通过引导连续波激光束通过旋转镜形成光片，从而确保有足够的光能照射自然水域中的小颗粒（~10 mm至~100 mm），同时保持颗粒的曝光时间短，避免图像模糊。一个初步的系统已经建立了一个超移动计算机和一个基于usb的信号发生器。π吗?我们提出对原型UWMPIV系统进行改进，使其能够测量更高的速度和湍流度，并且可以根据平均流动方向的变化来调整其方向，以避免面外运动引起的测量误差。改进后的系统将是紧凑的、多功能的，并允许长期观测（几天）。UWMPIV将被设置为一个自由漂浮的系统，用于测量小尺度湍流结构的垂直剖面，包括耗散率、熵和空气-水界面以下的表面散度。目的是提供对自由表面湍流及其对通过空气-水界面的气体传递的影响的理解。更广泛的影响：在概述如何在教育和公共宣传中使用这种紧凑的原位PIV系统方面，pi做得非常好。除了用于各种土木工程课程的实验室和案例研究外，该提案还为两名研究生提供了资金。与威斯康辛码头探索世界的合作听起来是一个接触公众的绝佳机会。PIV可以提供一个非常不同的海洋流动视角，因为它可以非常详细地解析2D场。典型的海洋观测很少能做到这一点，因为它们通常是稀疏的。