On the Theory of the Additional Loss at the Pipe Entrance in Viscous Fluid : 1st Report, On the Influence of Rounded Entrance

Abstract

When a viscous fluid flows out of a big vessel into a pipe, a part of fluid energy is lost at the entrance region by fluid friction. In the case of a rounded entrance, the author determined the dissipation energy by the method of dividing the region into two parts and assuming the stream functions satisfying the boundary conditions at every region, and showed by numerical calculation how the dissipation energy and the coefficient of a pipe end correction vary with the radius of a rounded entrance. The results are as follows. (1) When the radius of a rounded entrance approaches zero, the value of the dissipation energy approaches that of the strict solution obtained by Weissberg. (2) When its radius increases, the values of the dissipation energy and the coefficient of a pipe and correction increase gradually, and these tendencies are shown distinctly.