Statistical Characteristics and Time Autocorrelation Coefficients of the Turbulent Swirl Flow in Pipe

Abstract

In this paper is presented experimental investigation of the turbulent swirl flow in pipe generated by three axial fans ofvariousgeometries. One of these fans (model ZP) generates Rankine swirl, while other two, industrial fans, produce mainly solid bodycircumferential velocity profile. One-component laser Doppler anemometry (LDA) is employed in this research. Downstreamtransformations of the non-dimensional time-averaged velocity profiles are analyzed. Distributions of turbulence levels arediscussed for all three fans in both measuring sections, as well as statistical moments of higher orders for fluctuationsin theaxial, radial and circumferential directions. Applied correlation theory revealed turbulence structure and its statistical nature.