Localized velocity and turbulence measurement in turbulent swirling flows using laser Doppler anemometry

Turbulent swirling water flow in a pipe has complex velocity distributions with special measurement problems tor experimental work. Some of these problems are described in the introduction to the paper along with comments on the basic characteristics of turbulent swirling flow.The form of laser Doppler anemometer used is briefly noted, with some special optical features developed to suit this class of flow. Experience during some two years of comprehensive experimentation is then outlined, including comment on the data processing system.Results from experiments with tangentially injected water flow in 50 mm bore pipes up to 60 diameters long are reported, with local measurements of mean velocity and turbulence intensity. The variation of mean velocity components and turbulence intensity with radius and distance along the pipe are discussed with a few comparisons of results obtained from other experimental techniques, e.g. pitot-static probe and hot films.For the particular problem examined here it would have been difficult, if not impossible, to obtain the measurements using a technique other than laser anemometry.