Trial production of a new wind tunnel with directly controlled fans to simulate fluctuations in velocity and direction of natural wind

试制新型直控风扇风洞，模拟自然风的风速和风向波动

基本信息

批准号：
07555637
负责人：
NOMURA Takashi
金额：
$ 3.46万
依托单位：
Nihon University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07555637/
关键词：
natural wind wind tunnel AC servomotor velocity fluctuation turbulence scale モーター制御

项目摘要

The present project has been conducted to develop a new wind tunnel to simulate fluctuations in velocity and direction of natural wind. We made for trial a wind tunnel of which fans are driven by an AC servomotor. The servo motor is controlled by computer-generated voltage histories. The maximum wind velocity is 13 m/s. The generated wind velocity is measured by a hot wire anemometer.The measured velocity histories under step-wise voltage changes show that the wind velocity can change abruptly within a infinitesimal time less than a quarter second. However, in the cases that the target velocity is zero, it takes about one second because the wind is not able to stop due to its inertia even after the fan has stopped rotating. The measured velocity histories under sinusoidal voltage changes show that the wind velocity varies sinusoidally, except for the cases that the lowest velocity is zero.We have next conducted a series of experiments where the target velocity fluctuations obey the Karman spectrum. The measured velocity histories and their power spectra show that the new wind tunnel can reproduce not only details of the target velocity fluctuation but also its statistics. Especially, velocity fluctuation with quite large turbulence length scale can be achieved easily. There is a limitation in generating high frequency fluctuation beyond several cycles per second.These results show that the present new wind tunnel possesses sufficient ability to simulate velocity fluctuation of natural wind as far as the longitudinal fluctuations are concerned.As a preliminary investigation to control wind direction, we investigated the effect of inhalation by two wind tunnels in tandem alignment, and found that it is not effective. It is now planned to control wind direction by combining air flows from two wind tunnels aligned with a horizontal angle.

目前的项目旨在开发一个新的风洞来模拟自然风的速度和方向的波动。我们制作了一个风洞来进行试验，其中风扇由交流伺服电机驱动。伺服电机由计算机生成的电压历史控制。最大风速为13 m/s。产生的风速由热线风速计测量。在电压阶跃变化下测量的速度历史表明，风速可以在小于四分之一秒的极短时间内突然变化。然而，在目标速度为零的情况下，由于即使风扇停止旋转，风也由于惯性而无法停止，因此需要大约一秒的时间。正弦电压变化下测得的速度历史表明，除了最低速度为零的情况外，风速呈正弦变化。接下来我们进行了一系列实验，目标速度波动服从卡门谱。测量的速度历史及其功率谱表明，新的风洞不仅可以再现目标速度波动的细节，还可以再现其统计数据。特别是，可以很容易地实现具有相当大的湍流长度尺度的速度脉动。产生超过每秒几个周期的高频脉动存在局限性。这些结果表明，就纵向脉动而言，现有的新型风洞具有足够的能力来模拟自然风的速度脉动。作为控制风的初步研究方向上，我们研究了串联排列的两个风洞的吸气效果，发现效果并不好。现在计划通过合并来自两个以水平角度排列的风洞的气流来控制风向。