Numerical Study of the Entrance Flow and Its Transition in a Circular Pipe (2)

The experimental data and results of prior investigations lead to defining the problem of the transition from laminar to turbulent flow in a circular pipe. So far, the subject has been a major problem for hydro-and aeromechanics, and yet it seems not to have been clearly defined. Therefore, the flow field of a circular pipe is examined with particular emphasis on the entrance and transition length , using the two-dimentional computational scheme presented at the Symposium on Mechanics for Space Flight-1985 at ISAS. Symmetric disturbances were superimposed on points near the inlet and wall of the pipe. It was, for the first time, found that the transition length is predicted fairly satisfactorily by the computational simulation.