Fluorescent PIV using Atomized Liquid Particles


  • Adit S. Acharya Virginia Polytechnic Institute and State University
  • K. Todd Lowe Virginia Polytechnic Institute and State University
  • Wing F. Ng Virginia Polytechnic Institute and State University




PIV, Fluorescent, Seeding, Atomized, Liquid


It is shown that aerosolized fluorescent particles generated using a Venturi-type atomizer, from a solution of fluorescent Kiton Red 620 dye in a water/glycol fluid, provide effective flow seeding for fluorescent PIV. The atomized liquid particles were found to be of acceptable size for PIV purposes, with 92% of detected particles by number concentration measuring < 1 μm in diameter. A PIV application was conducted in a wind tunnel (freestream velocity U = 27 m/s), using the particles for measurement of the boundary layer flow approaching a forward-facing step (approach boundary layer momentum thickness Reynolds number of Reθ = 5930), to identify potential benefits in near-wall regions normally affected by unwanted laser reflections from tunnel surfaces. Particles were generated from solutions with dye molar concentrations of 2.5 × 10−3 and 1.0 × 10−2 mol/L, and PIV images were obtained for both elastic Mie scattering and filtered, Stokes-shifted fluorescent light. Raw images indicate that the fluorescence yield of the 1.0 × 10−2 mol/L solution provides PIV images with high contrast, even in the near-surface regions where Mie scattering images are highly affected by surface reflections. Boundary layer profiles are processed in the adverse pressure gradient region leading up to the forward-facing step, where the fluorescent PIV performed comparably to the most optimized Mie scattering PIV; both obtained data as near to the wall as 30 μm, or 2 viscous wall units in our flow of interest. These results indicate that the new seeding method holds excellent promise for near-surface measurement applications with more complicated three-dimensional geometries, where it is impossible to arrange PIV cameras to reject surface-scattered light.

Author Biography

Adit S. Acharya, Virginia Polytechnic Institute and State University

Adit Acharya is a Ph.D. candidate in Aerospace Engineering at Virginia Tech, advised by Dr. Todd Lowe. For the past two years, his research has focused on fluid measurement techniques, primarily involving seeding methods for laser-based diagnostics. In 2020, Adit won the National Defense Science and Engineering Graduate Fellowship (NDSEG), and is now conducting experimental research on vortex dynamics sponsored by the Office of Naval Research (ONR).