In this study, time-resolved particle image velocimetry (PIV) was performed in wall-parallel planes to investigate both the time evolution of structures in the flow as well as the 3D spatio-temporal spectrum. In particular vortex signatures in wall-parallel planes were studied which were found to correspond closely with the signature of hairpin vortices found in wall-bounded shear flows. Considering the convection velocity of different streamwise-spanwise scale pairs calculated from the spatio-temporal spectrum, it was found that the average convection velocity of highly energetic scales in the range 1.5 < λx/δ < 5.0 and 0.5 < λz/δ < 1.0 was close to the convection velocity of the vortex signatures. Also, this range of wavelengths is similar in size to the streamwise-elongated structures around which these vortices often appear.
|Original language||English (US)|
|State||Published - Jan 1 2011|
|Event||7th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2011 - Ottawa, Canada|
Duration: Jul 28 2011 → Jul 31 2011
|Other||7th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2011|
|Period||7/28/11 → 7/31/11|