Three-dimensional flow separation over a surface-mounted hemisphere in pulsatile flow

Effects of highly pulsatile inflow frequency on surface-mounted bluff body wakes

“…The energy spectral density profiles reflect the relationship between wake structure and k observed in the flow fields -natural shedding and wake turbulence decreasing with increasing k. 100 cycles. For more information on the experimental set-up, data processing and physics observed refer to Carr & Plesniak (2016). From the phase-averaged PIV data and phase-averaged DNS, a series of boundary layer profiles have been measured at three positions all centred on the hemisphere in the spanwise direction, x/D = −1, 1, 2.5, z/D = 0.…”

“…In the present study, the arch vortex (taken with the image of the arch vortex in the ground plane) are produced in such a way that they oppose the primary flow direction. As detailed in Carr & Plesniak (2016), the upstream self-induced propagation direction, along with the near-wall boundary layer reversal, account for the unexpected upstream motion of the wake/arch vortex during decelerating inflow. Assumed in these prior studies, and the present comparison of p and T * , is validity of the image of the arch vortex.…”

“…To validate the numerical solver, a series of phase-averaged DNS was computed to compare with the phase-averaged PIV at – within the range discussed in the present study. The phase-averaged PIV data used for validation were originally published and discussed in Carr & Plesniak (2016). With the focus of benchmarking, a series of DNS were computed using inlet conditions that match those measured in the experiments using a Dantec MiniCTA positioned in the free stream.…”

“…To match the parameters of the PIV data, the simulation data were phase averaged over 100 cycles. For more information on the experimental set-up, data processing and physics observed refer to Carr & Plesniak (2016).…”

“…In Carr & Plesniak (2016), a surface-mounted hemisphere was subjected to a highly pulsatile free-stream flow at a reduced frequency of . Velocity fields were computed from phase-averaged particle image velocimetry (PIV) in two orthogonal planes which bisect the hemisphere's near wake.…”