円管内助走区間における振動流

第2報 近似解析と非定常粘性抵抗係数

抄録

An approximate solution for the velocity profiles for the oscillatory flow in the inlet region of a circular tube was obtained on the basis of the author's previous work, and it was compared with the experimental results and numerical results.
To estimate the pressure drop, the frequency-dependent unsteady viscous friction coefficient in the inlet region of a circular tube was defined and derived.
The results show that the magnitude of the friction coefficient is nearly proportional to the square root of the frequency in the high frequency region and to the square root of the reciprocal of the distance from the entrance of the pipe in the inlet region, and it is verified that in a sufficiently high frequency region the same friction coefficient as for the oscillatory flow in the developed region can be applied for the oscillatory flow in the inlet-region.