Axisymmetric turbulent statistics of long slender circular cylinders

The experimental evidence leads us to believe that long slender circular cylinders have similar axisymmetric turbulent statistics along most of their axial length. The respective boundary layer reaches a maximum thickness (delta) with no further downstream net growth. Despite their small radius (a), these long cylinders still own high radius-based Reynolds numbers (Re(a)) as well as transverse curvatures (delta/a). The influence of these flow conditions (and others) on the turbulent statistics is still chiefly unknown. The present effort begins an investigation that targets axial similarity (or homogeneity) of the long thin cylinder statistics. The database is a collection of previous experimental measurements and observations as well as the present computational results by the large-eddy simulation methodology. Interestingly, this investigation shows that reaching axial homogeneity is reliant essentially on Re(a) with lesser influence by the transverse curvature. But the Re(a) value depends on the turbulent statistic of interest. Likewise, this same result was found for spotting the radial location of the respective statistical peak. Axial homogeneity starts near the cylinder wall then migrates outward radially with increasing Re(a) until full saturation through the turbulent intermediate layer. [doi:10.1063/1.3609272]