On the Viscous Flow in Rounded Pipe Entrance (When Two-Dimensional Flow is Very Slow)

The study of the viscous flow in the rounded pipe entrance which is seen in such as capillary viscometers，is not yet accomplished. It is exceedingly difficult to solve Navier-Stokes equations of motion exactly， so that authors try to obtain their solutions in the case of two-dimensional flow by assuming that their inertia terms are omitted as the fluid velocity is very slow. Further， assuming that the stream function has the expansion of descending power series，the matters as under are obtained theoretically; the stream lines，the velocity distributions，the pressure distributions and the frictional coefficient in the rounded pipe entrance. Then authors try to know the region of Reyno1ds number in which this theory is established by the experimental analysis. But the pressure loss is very small when the fluid velocity is very slow，so that it is exceedingly difficult to measure the velocity and pressure distributions. Therefore， the relations among the theoretical stream lines， the experimental stream lines and Reynolds number are investigate