Abstract
Effect of repeatedly imposed acceleration on transition to turbulence in transient circular pipe flow has been investigated experimentally together with the laminar analytical solution. The acceleration pattern in the present study is a combination of two constant accelerations from rest in which the second acceleration is larger than the first one. The axisymmetric Navier-Stokes equations are solved for the present target flow to compare the experimental results before the appearance of turbulence. As a result, the present impositions of the repeated acceleration on the pipe flow cannot distinctly suppress transition to turbulence within the present adopted experimental conditions. However, the laminar solution obtained for the accelerating pipe flow was found to be valid for the present target flow until transition to turbulence and, after the turbulence appeared, the axial velocity was approximated with the 1/nth power law for a steady flow.
