Reynolds number effects in a turbulent pipe flow for low to moderate Re

We present in this paper high resolution, two-dimensional LDV measurements in a turbulent pipe Row of water over the Reynolds number range 5000-25000. Results for the turbulence statistics up to the fourth moment are presented, as well as power spectra in the near-wall region. These results clearly show that the turbulence statistics scaled on inner variables are Reynolds-number dependent in the aforementioned range of Reynolds numbers. For example, the constants in the dimensionless logarithmic mean-velocity profile are shown to vary with Reynolds number. Our conclusion that turbulence statistics depend on the Reynolds number is consistent with results found in other flow configurations, e.g., a channel flow, Our results for the pipe flow, however, lead nevertheless to quite different tendencies. (C) 1997 American Institute of Physics.