High speed cameras for time-resolved laser based turbulence measurements

用于基于时间分辨激光的湍流测量的高速相机

• 批准号: RTI-2017-00375
• 负责人: Nedic, Jovan
• 金额: $ 10.93万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=616658
• 关键词: speed; cameras; time; resolved; laser

This RTI application will give fluid dynamics researchers within the McGill Mechanical Engineering Department the ability to obtain time-resolved measurements of all three velocity components, which is paramount for a deeper physical understanding of turbulent flows and fluid dynamics in general. Obtaining such measurements within a spatial plane provides greater insight into the dynamical aspects of the flow field, such as the dynamics of coherent structures and the spatial evolution of the flow field, which are crucial for the development of flow control strategies and models that aim at reducing the environmental impact of the aerospace and transportation sectors, the dispersion of pollutants within the atmosphere and energy harvesting from wind and water turbines, all of which are strategic research areas within McGill and NSERC. A common experimental method that facilitates this is the optical method of particle image velocimetry (PIV). This technique is non-intrusive which, in its simplest form, requires a flow to be seeded with particles that are illuminated with a laser light sheet; a camera is used to obtain images with a fixed time difference and hence velocity information is extracted by analysing the movement of the particles between two successive images. Using a single camera one obtains two velocity components (planar PIV), however, for all three velocity components one would need two identical cameras (stereo PIV). The department currently has a Dantec time-resolved planar PIV system and it is proposed that this system be upgraded to a stereo-PIV system, which will allow researchers to take time-resolved measurements of all three velocity components within a plane. Having two cameras also allows for other advanced measurements such as joint planar laser induced fluorescence (PLIF) and PIV measurements (stereo-PIV plus PLIF measurements obtained using current camera), extended field of view PIV measurements (two cameras in a side-by-side arrangement), multiscale turbulence measurements (two or more cameras focusing on the same plane with different magnifications) and combined digital image correlation (DIC) and PIV measurements to investigate fluid-structure interactions. A number of projects have already been identified for the proposed equipment, including long and short wave instability of vortex pairs, evolution of vortex rings, decay of multiscale generated wing-tip vortices and flow through a synthetic model (or phantom) of the human larynx during phonation. The PI will offer special training courses for these measurement techniques, which will be made available to HQPs across the department and faculty. The PI alone anticipates at least ten HQPs to be trained on this equipment over the next five years; one undergraduate student has already started their project whilst two PhDs will begin in January 2017, thus highlighting the urgent need for the equipment.

该RTI应用程序将使麦吉尔机械工程系的流体动力学研究人员能够获得所有三个速度分量的时间分辨测量值，这对于更深入地了解湍流和流体动力学至关重要。在空间平面内获得这样的测量结果可以更好地了解流场的动态方面，例如相干结构的动态和流场的空间演变，这对于旨在减少航空航天和运输部门的环境影响的流量控制策略和模型的开发至关重要，污染物在大气中的扩散以及风力和水力涡轮机的能量收集，所有这些都是麦吉尔大学和NSERC的战略研究领域。 一种常见的实验方法，促进这是粒子图像测速（PIV）的光学方法。这种技术是非侵入性的，在其最简单的形式中，需要用激光片照射的颗粒接种流;相机用于获得具有固定时间差的图像，因此通过分析两个连续图像之间的颗粒的运动来提取速度信息。使用单个摄像机可以获得两个速度分量（平面PIV），然而，对于所有三个速度分量，需要两个相同的摄像机（立体PIV）。该部门目前拥有一个Dantec时间分辨平面PIV系统，并建议将该系统升级为立体PIV系统，这将使研究人员能够对平面内的所有三个速度分量进行时间分辨测量。拥有两台相机还可以进行其他高级测量，例如联合平面激光诱导荧光（PLIF）和PIV测量（使用当前相机获得的立体PIV加PLIF测量），扩展视野PIV测量（两个摄像机并排布置），多尺度湍流测量（两个或多个摄像机以不同的放大率聚焦在同一平面上），并结合数字图像相关（DIC）和PIV测量来研究流体-结构相互作用。已经为拟议的设备确定了一些项目，包括涡对的长波和短波不稳定性、涡环的演变、多尺度产生的翼尖涡的衰减以及发声期间通过人喉的合成模型（或幻影）的流动。PI将为这些测量技术提供特殊的培训课程，这些课程将提供给整个部门和教师的HQP。仅PI就预计在未来五年内至少有10名HQP将接受该设备的培训;一名本科生已经开始了他们的项目，而两名博士将于2017年1月开始，因此突出了对该设备的迫切需求。