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首页> 外文会议>25th Conference on Agricultural and Forest Meteorology and 12th Joint Conference on the Applications of Air Pollution Meteorology with Aamp;WMA and Fourth Symposium on the Urban Environment May 20-24, 2002 Norfolk, Virginia >FINE SCALE TURBULENCES MEASUREMENTS IN CASES99 USING TRIPLE-HOT-FILM ANEMOMETERS
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FINE SCALE TURBULENCES MEASUREMENTS IN CASES99 USING TRIPLE-HOT-FILM ANEMOMETERS

机译：使用三热膜测光法在CASES99中进行精细的尺寸测量

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摘要

The basic ground-based turbulence and flux sensors used in the Cooperative Atmospheric Surface Exchange Study (CASES-99) were three-dimensional sonic anemometers (CSAT3, Campbell Scientific Inc.). Sonic anemometers are likely to have limited high frequency response when the turbulence scale is too small to be resolved by their 10 cm path length (Kaimal and Finnigan, 1994). Therefore, their use near the ground and in very stable conditions is in question. In these cases, a very small, fast response sensor is needed to resolve eddies responsible for transport. Hot- wire and hot-film anemometers are the only sensors currently available that meet these size and speed requirements. Basic problems using hot-film technology in open air can be grouped as follows. (1) Those problems that are associated with voltage drift due to changing environmental temperatures. (2) Those problems that are associated with acceptable mean wind approach angles. Multi-film probes must be pointing into the wind. When the wind approach angle is large (>+- 54.7° from parallel to the probe axis for the probes used herein), flow interference by probe supports and adjacent -films makes the data unusable. Even at mean approach angles near parallel to the probe axis, fluctuating wind vector directions outside the acceptance cone in turbulent flows cause significant errors due to non-unique solutions to heat transfer equations. (3) Those problems that are associated with sensor calibration due to sensor response deviation from true cosine law, from film aging, from non-ideal probe geometry due to inherent construction error, and from difficult alignment in the field of the small size films.
机译：合作大气表面交换研究（CASES-99）中使用的基本地基湍流和通量传感器是三维声速风速计（CSAT3，坎贝尔科学公司）。当湍流尺度太小而无法通过其10 cm的路径长度来解决时，声速风速计可能具有有限的高频响应（Kaimal和Finnigan，1994）。因此，在地面附近和非常稳定的条件下使用它们是有问题的。在这些情况下，需要一个很小的快速响应传感器来解决负责运输的旋涡。热线和热膜风速计是目前仅有的满足这些尺寸和速度要求的传感器。在露天使用热膜技术的基本问题可以归纳如下。 （1）与环境温度变化引起的电压漂移相关的问题。 （2）与可接受的平均风向角有关的问题。多层薄膜探头必须指向风中。当进风角度较大时（对于此处使用的探针，平行于探针轴的平行度为+/- 54.7°），探针支撑件和相邻的胶片会干扰流动，从而使数据无法使用。即使在接近平行于探头轴线的平均接近角度下，由于传热方程的非唯一解，在湍流中在接收锥外波动的风矢量方向也会引起很大的误差。 （3）与传感器校准有关的那些问题是由于传感器响应偏离真实余弦定律，膜老化，由于固有构造误差导致的非理想探头几何形状以及由于在小尺寸膜领域中难以对准而引起的。

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