Structure of Turbulent Channel Flow Perturbed by a Wall-Mounted Cylindrical Element

The current study reports structural modifications imposed in fully developed, turbulent channel flow by an isolated wall-mounted circular cylinder. The cylinder extended into the logarithmic layer of the flow, perturbing the larger flow scales that embody a significant fraction of the turbulent kinetic energy and Reynolds shear stress. Hot-wire measurements were made in the wake of the wall-mounted circular cylinder at multiple wall-normal and streamwise positions. Besides observing the expected mean velocity deficit in the wake of the cylinder, a secondary peak in streamwise Reynolds normal stress away from the wall was observed, coupled with suppression of the near-wall peak native to the incoming unperturbed, turbulent flow. These observations are similar to those made by Ryan et al. (“Effects of Simple Wall-Mounted Cylinder Arrangements on a Turbulent Boundary Layer,” AIAA Journal, Vol. 49, No. 10, 2011, pp. 2210–2220) for a wall-mounted cylinder protruding into the logarithmic layer of a turbulent b...