Abstract
An axisymmetric unsteady flow of incompressible viscous liquid in a circular rigid tube was studied for some aspects. Change of the axial velocity profile at a cross section, due to a step change of the flow rate, was obtained analytically except the inletlength region. In the experiment a laser Doppler velocimeter was used to measure the velocity profile without disturbing the flow. The experimental results are found to be in good agreement with the predictions of the analysis and the base of the so-called frequency dependent viscous friction for the unsteady flow in the tube was supported by this research from the viewpoint of the local dynamic behavior of the flow.
