Characterization of a Low-Speed Wind Tunnel With Variable Thermal and Turbulent Properties

• Main Authors: Kuo-Hsien,Hsu, 許國賢
• Other Authors: Jong-Shinn,Wu
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/10941189636448923413

碩士 === 國立交通大學 === 機械工程系 === 89 === ABSTRACT An open-air vertical, circular wind tunnel has been constructed to generate the nearly uniform high- and low- turbulence flow field at various temperatures, which is capable of producing free stream with mean velocities of 0.5~2m/s, turbulence intensities of 1.5~24.7%, and temperature of 300~900K. Turbulence environments are controlled by the different sizes of the turbulent generating disk. Laser Doppler Velocimeter is used to characterize the turbulence properties of the wind tunnel, including the mean streamwise velocity, turbulent intensity, probability density function and energy power spectrum. Integral length scale and Komogorov microscale are computed using Taylor hypothesis and assuming isotropic turbulence theory, respectively. A relatively homogeneous region about 20 mm in the middle of the tunnel exit is identified, which is wide enough for future droplet experiments.