Experimental Investigation of a Tandem Cylinder System With a Yawed Upstream Cylinder

The unsteady flow field produced by a tandem cylinder system with the upstream cylinder yawed to the mean flow direction is investigated for upstream cylinder yaw angles from $α=60 deg$ to $α=90 deg$⁠. Multipoint fluctuating surface pressure and hot-wire measurements were conducted at various spanwise positions on both the upstream and downstream cylinders. The results indicate that yawing the front cylinder to the mean flow direction causes the pressure and velocity spectra on the upstream and downstream cylinders to become more broadband than for a regular tandem cylinder system, and reduces the magnitude of the peak associated with the vortex-shedding. However, spanwise correlation and coherence measurements indicate that the vortex-shedding is still present and was being obscured by the enhanced three-dimensionality that the upstream yawed cylinder caused. When the cylinder was yawed to $α=60 deg$⁠, the pressure fluctuations became extremely broadband and exhibited shorter spanwise correlation.