Experiments on transition to turbulence in a constant-acceleration pipe flow
Date of Original Version
Experiments were conducted to study transition to turbulence in pipe flows started from rest with a linear increase in mean velocity. The data were taken at the Unsteady Flow Loop Facility at the Naval Underwater System Center, using a 5-cm diameter pipe 30 meters long. Instrumentation included static pressure, wall pressure, and wall shear stress sensors, as well as a laser Doppler velocimeter and a transient flowmeter. A downstream control valve was programmed to produce nearly constant mean flow accelerations, a, from 2 to 12 m/s2. In each of 37 runs, the time of transition to turbulence was the same throughout the pipe to within ±30 ms, indicating a global instability. As acceleration increased, the transition Reynolds number ReD increased monotonically from 2 × 105 to 5 × 105. Other dimensionless transition parameters are also presented, the simplest and most effective of which is T* ≈ 400±10 percent for the present experiments, where T* = tlr (a2/v)1/3 and v is kinematic viscosity. © 1989 by ASME.
Journal of Fluids Engineering, Transactions of the ASME
Lefebvre, P. J., and F. M. White. "Experiments on transition to turbulence in a constant-acceleration pipe flow." Journal of Fluids Engineering, Transactions of the ASME 111, 4 (1989): 428-432. doi:10.1115/1.3243663.