2020 Volume 5 Pages 25-30
In this study effectiveness of microbubbles as tracer of PIV measurement is investigated. Test case is turbulent separated flow over a backward-facing step (Re=3700,110000). In the present experiment microbubbles (mean diameter is 42 μm) are uniformly suspended in the water. Mean velocity and Reynolds stresses in the separated shear layer are measured by PIV using these microbubbles as tracer particles. Results are compared with those measured by PIV using conventionalsolid particles as tracer in the same experimental conditions. Distributions of mean velocity, Reynolds normal and shear stresses measured by PIV with microbubbles are in good agreement with those measured by PIV with conventional solid particles. It is suggested that microbubbles can be used as tracer of PIV for the measurement of turbulent separated flow in this Re range.