Lagrangian particle tracking at large Reynolds numbers

Area of Science:

• Fluid Dynamics
• Turbulence Research
• Particle Tracking

Background:

• Lagrangian frame is ideal for studying transport and mixing in fluid turbulence.
• Previous Lagrangian measurements were limited to lower Reynolds numbers (Rλ ≈ 10³).
• Eulerian methods using hot-wire anemometry have been extensively studied but have limitations.

Purpose of the Study:

• To present a novel Lagrangian particle tracking setup in the Max Planck Variable Density Turbulence Tunnel (VDTT).
• To enable high-resolution particle tracking at high Taylor scale Reynolds numbers (100–6000).
• To validate the suitability of specific tracer particles for this experimental setup.

Main Methods:

• Detailed description of the imaging setup within a pressurized facility.
• Utilized laser illumination and a specific particle seeding mechanism.
• Employed KOBO Cellulobeads D-10 particles as tracers and analyzed their properties.

Main Results:

• The VDTT setup successfully achieves Taylor scale Reynolds numbers between 100 and 6000.
• KOBO Cellulobeads D-10 particles show no significant charge.
• Particle inertia has a negligible impact on results across various experimental conditions.

Conclusions:

• The presented Lagrangian particle tracking setup is suitable for high Reynolds number turbulence studies.
• The validated tracer particles and methodology overcome previous limitations in Lagrangian measurements.
• This work paves the way for more in-depth investigations of turbulent transport and mixing.