円管乱流における管摩擦係数の信頼性－平均速度分布からの検証

抄録

The consistency between the mean velocity profile and the friction factor measured at the Hi-Reff at AIST, NMIJ was investigated. The velocity profile data was fitted to a velocity profile form based on the log law, and an equation for the friction factor was derived by integration. The derived equation for the friction factor accurately represents the friction factor data. The deviation from the friction factor data is less than 0.6%. This small deviation indicates the high reliability of the measurement data at the Hi-Reff. Based on the equations for the friction factor derived using the mean velocity profile, the best-fitting constants for the friction factor data are also proposed. For the Reynolds number region above 10⁶, the Kármán constant is estimated to be 0.383.