REYNOLDS-NUMBER EFFECTS IN A TURBULENT PIPE-FLOW FOR LOW TO MODERATE RE

We present in this paper high resolution, two-dimensional LDV measurem ents in a turbulent pipe Row of water over the Reynolds number range 5 000-25000. Results for the turbulence statistics up to the fourth mome nt are presented, as well as power spectra in the near-wall region. Th ese results clearly show that the turbulence statistics scaled on inne r variables are Reynolds-number dependent in the aforementioned range of Reynolds numbers. For example, the constants in the dimensionless l ogarithmic mean-velocity profile are shown to vary with Reynolds numbe r. Our conclusion that turbulence statistics depend on the Reynolds nu mber is consistent with results found in other flow configurations, e. g., a channel flow, Our results for the pipe flow, however, lead never theless to quite different tendencies. (C) 1997 American Institute of Physics.