壁面粗度の急変化における円管乱流の非平衡挙動

抄録

Non-equilibrium behavior of the turbulent pipe flow subjected by sudden change of the wall roughness has been investigated experimentally. The mean velocity, streamwise turbulent intensity and the local wall shear stress were measured for the initial stage of the process after sudden change wall condition from rough to smooth. The mean velocity show acceleration before approaching to fully-developed smooth wall flow. The local wall shear stress shows the overshoot behavior over the relaxation process. Gradient of the logarithmic velocity approach to fully-developed smooth wall flow in the early stages.