抄録
The Poiseuille flow through a circular tube as affected by the presence of a fixed spherical obstacle with its center on the axis of the tube is considered on the basis of the Stokes approximation. Expressions for the resultant force acting on the sphere and for the pressure difference which must be added to maintain the total flux through the tube at the value corresponding to the case of absence of the obstacle are obtained correctly to (a⁄r0)5, where a and r0 are the radii of the sphere and the tube respectively. If terms of the order of (a⁄r0)2 can be neglected, the magnitude of the resistance is shown to be equal to that of a sphere moving with a constant velocity along the axis of a tube, which was first obtained by Ladenburg.
