Flow visualization and particle image velocimetry (PIV) measurements were performed to reveal the three-dimensional structure of high frequency vortex shedding behind a V-gutter.
Tubular structures connecting adjacent vortices were found in front of the shedding vortex in the visualization image. PIV measurements permitted quantification of these tubular structures, although there were many errors in the results of these measurements. The overlap and moving average methods were applied to PIV-measured velocities to increase spatial resolution and to reduce errors. It was shown that the vortex shedding pattern behind a V-gutter forms into streamwise structures. The streamwise vorticity reached 20% to 100% of the spanwise vorticity at the same location. An FFT (Fast Fourier Transform) analysis was performed using the PIV data to determine the streamwise vorticity scale. This resulted in a calculated vortex diameter of 5mm, and this was verified by measurements taken from the visualization images.