Further experiments for mean velocity profile of pipe flow at high Reynolds number

高レイノルズ数における円管流平均速度分布に関するより詳細な実験

古市 紀之*; 寺尾 吉哉*; 和田 裕貴   ; 辻 義之*

Furuichi, Noriyuki*; Terao, Yoshiya*; Wada, Yuki; Tsuji, Yoshiyuki*

This paper reports further experimental results obtained in high Reynolds number actual flow facility in Japan. The experiments were performed in a pipe flow with water, and the friction Reynolds number was varied up to = 5.3 10. This high Reynolds number was achieved by using water as the working fluid and adopting a large-diameter pipe (387 mm) while controlling the flow rate and temperature with high accuracy and precision. The streamwise velocity was measured by laser Doppler velocimetry close to the wall, and the mean velocity profile, called log-law profile = (1/) ln(y) + , is especially focused. After careful verification of the mean velocity profiles in terms of the flow rate accuracy and an evaluation of the consistency of the present results with those from previously measurements in a smaller pipe (100 mm), it was found that the value of asymptotically approaches a constant value of = 0.384.