Lagrangian measurement of fluid and particle motion using a field‐deployable Volumetric Particle Imager (VoPI)
Lagrangian measurement of fluid and particle motion using a field‐deployable Volumetric Particle Imager (VoPI)
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使用可现场部署的体积粒子成像仪 (VoPI) 对流体和粒子运动进行拉格朗日测量
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
E. Variano
中科院分区：
文献类型：
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作者：
I. Tse;E. Variano
我们描述了可现场部署的体积粒子成像仪（VoPI）的开发以及使其能够原位测量三维粒子轨迹的方法。 VoPI 具有获取体积中三分量粒子速度记录的独特能力。该设备采用细长的单摄像头设计，非常适合光学访问环境中的研究地点，包括珊瑚礁和沼泽内部等难以到达的地方。与其他水下测量技术不同，VoPI 采用散焦成像方法，依靠环境光代替激光进行粒子照明。我们描述了该设备的构造、校准和验证。我们还通过测量分散在高雷诺数湍流中的被动示踪粒子的速度统计来证明 VoPI 的能力。通过测量这些拉格朗日速度记录中的速度方差和积分时间尺度，我们可以直接根据 VoPI 测量值计算湍流扩散率。
We describe the development of a field‐deployable Volumetric Particle Imager (VoPI) and the methods that enable it to measure three‐dimensional particle tracks in situ. The VoPI has the unique ability to obtain three‐component particle velocity records in a volume. The device has a slender, single‐camera design ideal for optically accessing study sites in the environment, including hard‐to‐reach places like the inside of coral reefs and marshes. Unlike other underwater measurement techniques, the VoPI implements a defocused imaging method that relies on ambient light in place of laser light for particle illumination. We describe the construction, calibration and validation of this device. We also demonstrate the VoPI&s abilities by measuring velocity statistics of passive tracer particles dispersed in a high‐Reynolds‐number turbulent flow. By measuring velocity variances and integral timescales from these Lagrangian velocity records, we can compute the turbulent diffusivity directly from the VoPI measurements.