Positioning Devices For Measuring Spatial Velocity Correlations in Turbulent Swirl Flow in the Pipe by Hot-Wire Probes



M.R. Lečić,

Department of Fluid Mechanics, Faculty of Mechanical Engineering,

University of Belgrade,

Belgrade, Serbia

Email: acocic@mas.bg.ac.rs


Measuring spatial correlations of velocity is done by simultaneous measurement of velocity vector in two different measuring points. Usually, the points should be at a very small distance. While performing correlation measurements in turbulent swirling flow in the pipe, it is necessary to have very precise positioning of hot-wire probes, both by angle and distance. In this research, measurements of spatial correlations in such flow field are performed, for two different cases: velocity correlations in two points on different radial distance and in two points on different axial distance, parallel to the pipe axis. For such measurements two original devices for positioning of hot-wire probes are developed. With these devices appropriate angle positioning and radial and axial distance of hot-wire probes are achieved. Cross-correlation diagrams are also given in this article, as an illustration of capabilities of these original devices for hot-wire probes positioning.