ON THE DIRECTIONAL DEPENDENCE OF TURBULENCE PROPERTIES IN ANISOTROPICTURBULENT FLOWS

An examination is made of the consequences of a zero correlation betwe en fluctuations in velocity level and flow direction in a stationary a nisotropic turbulent flow. This zero correlation results from the fact that in a stationary turbulent flow fluctuations in both velocity lev el and flow direction are entirely random processes. In this paper thi s is considered to be an inherent property of stationary flow and util ised to simplify both the computation and the measurement of anisotrop ic turbulence. This new method shows several advantages compared to ea rlier methods. First, the spatial distribution of the flow turbulence has been shown to be a trigonometric function of the spatial parameter . Second, the relationship between Reynolds normal and shear stresses has been established. Third, when a two-dimensional flow field is conc erned, two measurements using a one-component LDA system are sufficien t to identify the turbulence. Until now it has been considered that th ree such measurements were necessary. The feasibility of the method, k nown as zero correlation method, has been analysed and demonstrated by experiment.