抄録
The hydrodynamic drag forces experienced by a circular disk freely-falling at right angles to the trajectory are measured by using the falling circular disk technique at low Reynolds numbers. The influences of the thickness of circular disks on the hydrodynamic force are investigated. It is made clear that the drag forces are approximated by the type of Oseen's drag at the Reynolds Numbers below 1.0. The results of flow visualizations show that the visualized streamlines deviate from Stokes's streamlines with increasing the Reynolds numbers, and the results support the conclusions of measurements for the hydrodynamic drag forces.
