Characterization of a Particle Image Velocimetry (PIV) Setup Using Vortex Shedding from Circular Cylinder at Low Reynolds Number

Every experimental setup needs to go through rigorous characterization tests to ensure measurement accuracy for validation. This study presents a comprehensive characterization of a Particle Image Velocimetry (PIV) setup using periodic vortex shedding of a circular cylinder, as it provides a robust benchmark for validating flow regimes due to the availability of well-characterized data of the Strouhal number across different Reynolds numbers. A circular cylinder of 25 mm diameter was studied at a Reynolds number of 4369 for validation of the setup employing both computational and experimental techniques. For computational analysis, ANSYS was the preferred software. Time-Resolved PIV was used to capture velocity and vorticity fields at a frame rate of 120 fps using a cross-correlation algorithm. Spectral analysis of the acquired data enabled the extraction of vortex shedding frequencies, while vorticity contours were generated using PIVLab and MATLAB to visualize the vortex street. Three independent experimental trials yielded Strouhal numbers of 0.1897, 0.1952, and 0.1952, with errors of 3.6777%, 0.9137%, and 0.9137% respectively, relative to the theoretical benchmark of 0.1968. Additionally, Fast Fourier Transform (FFT) analysis confirmed the dominant shedding frequencies, which correlated well with the data in the literature. Overall, the experimental, computational, and theoretical values were in close agreement, suggesting the PIV setup is reliable for studies at low Reynolds numbers.