The spatial changes of the wake of a circular cylinder immersed in a turbulent boundary layer over a flat plate

An experimental study was conducted immersing a small cylinder (D/δ = 0.0478, where D is the cylinder diameter and δ is the boundary layer at 99% of the freestream velocity) in a turbulent boundary layer (TBL) over a flat plate at six wall-normal distances. The cylinder was placed with the longitudinal axis towards the span-wise direction of the test section. Using 2D-2C Time-resolved Particle Image Velocimetry (TR-PIV) measurements were taken immediately downstream of the cylinder obtaining a field of view of 3.7δ-by-2.2δ in the streamwise-wall-normal plane. In this presentation, turbulent statistics for the different cases studied are shown and compared with each other and with experimental data of the canonical TBL i.e., without the cylinder. Statistical trends, including the recovery of the turbulent mean profile downstream of the cylinder disturbance and the evolution of the Reynolds shear stresses downstream of the cylinder wake are reported and compared across the cases. The trends show that for all the cases, the influence of the cylinder on the velocity profile remains strong as the cylinder is placed at a farther distance from the plate. The interactions of the cylinder wake with the turbulent boundary layer coherent structures are analyzed using conditional averaging, including conditional projection averaging (Saxton-Fox et al, 2022). The evolution of the cylinder wake downstream is observed to be affected, in both its amplitude and its advection, by local large-scale turbulent structures.