Visualization of Turbulent Flow Fields Around a Circular Cylinder at Reynolds Number 1.4×105 Using PIV

Abstract

This study investigates the experimental parameters of particle image velocimetry (PIV) to enhance the measurement technique for turbulent flow fields around a circular cylinder at a Reynolds number (Re) of 1.4×105. At the Korea Research Institute of Ships & Ocean Engineering (KRISO), we utilized the cavitation tunnel and PIV system to capture the instantaneous flow fields and statistically obtained the mean flow fields. An aspect ratio and blockage ratio of 16.7% and 6.0%, respectively, were considered to minimize the tunnel wall effect on the cylinder wakes. The optimal values of the pulse time and the number of flow fields were determined by comparing the contours of mean streamlines, velocities, Reynolds shear stresses, and turbulent kinetic energy under their different values to ensure accurate and converged results. Based on the findings, we recommend a pulse time of 45 μs corresponding to a particle moving time of 3–4 pixels, and at least 3,000 instantaneous flow fields to accurately obtain the mean flow fields. The results of the present study agree well with those of previous studies that examined the end of the subcritical flow regime.

Keywords

• circular cylinder
• turbulent flow fields
• piv (particle image velocimetry)
• high reynolds number
• cavitation tunnel