1226 THE COLAPIPE - A HIGH REYNOLDS NUMBER PIPE TEST FACILITY

Abstract

A new pipe test facility for investigations on high Reynolds number pipe flow turbulence (Rem≦ 1.5 X 106) was setup, namely the CoLaPipe. The facility is designed to be closed-return with two available test sections providing a length-to-diameter ratio of L/D = 148 and L/D = 79. We present intensive measurements on the development of the flow from laminar to turbulent flow state with respect to natural transition as well as artificial transition. Our focus is on the detection of the fully developed turbulent flow state due to the characteristic behavior of the mean flow and the higher order statistics, e.g. turbulence intensity, skewness and flatness. The influence of tripping devices, i.e. orifices with different blockage ratios, on this evolution is of great interest, respectively. Here the question arises whether the turbulent flow state can be induced earlier in streamwise direction or not, which is important for further experiments, like CICLoPE. As the turbulent flow state is important due to structural observations and the deduced scaling behavior, we present additional experimental results to shed light on some open questions, i.e. inner peak behavior. All presented measurements are conducted on a hydraulically smooth surface by using single-wire probes working in constant-temperature hot-wire anemometry mode.