抄録
In experimental studies of circular pipe flow the entrance of pipes is rounded for avoiding entrance eddies. Until now it is not considered well how such bellmouth entrances influence the flow in circular pipes. In this study, numerical calculation of flow in a circular pipe with a bellmouth entrance is done. The vorticity transport equation is solved by the finite difference method. The velocity, vorticity, and pressure drop are investigated in steady flow. Then, bellmouth effect is considered. It is found that the velocity distribution is not uniform at the end of the bellmouth entrance. We also calculated the equivalent length of the pipe with bellmouth in comparison with that of straight pipe, which equals approximately the results based on the boundary layer theory.
