Publications Details
Pulse-Burst PIV of an Impulsively Started Cylinder in a Shock Tube for Re > 105
Wagner, Justin W.; Demauro, Edwward P.; Casper, Katya M.; Beresh, Steven J.; Pruett, Brian O.
Here, the impulsive start of a circular cylinder in a shock tube was characterized with time-resolved particle image velocimetry measurements (TR-PIV) using a pulse-burst laser. Three Reynolds numbers Re of 1.07 × 105, 1.63 × 105 and 2.46 × 105 were studied adding insight into the transient process in the vicinity of the drag crisis. One symmetric vortex pair was shed from the cylinder at the lower Reynolds number prior to the wake going asymmetric in a fashion analogous to studies at lower Re. At Re ≥ 1.63 × 105, two or more symmetric vortex pairs occurred prior to asymmetry and the eventual transition to a von Kármán vortex street. The non-dimensional rise time for vortex shedding to begin, as quantified by wavelet analysis, was found to be lower at the two higher Re. Finally, the study indicates a transformation in the impulsive wake to occur at Re near the critical regime and may serve as a benchmark for high Re numerical solutions.