Long-range μPIV in the turbulent region of a jet, at high Reynolds numbers

Long-range μPIV in the turbulent region of a jet, at high Reynolds numbers

Fiscaletti, D.
Elsinga, G.E.
Westerweel, J.

2013-07-03

The present work involves the investigation of the fine scale motions in the turbulent region of a high Reynolds number air jet. In the fully developed region of the jets, the small scales of turbulence are assumed to be isotropic, and expected to contain elongated vortices (worms), whose diameter scales with the Kolmogorov length scale. Aimed at capturing the worms, a long-range μPIV system is developed. The main design parameters of the PIV experiment are set on the basis of a hot-wire characterization of the flow. Furthermore, a benchmark hot-wire acquisition allows a validation of the present μPIV measurements, by comparison of the main statistics. In the implementation of the measurement technique, the low concentration of seeding particles and the short depth of focus represent both the main challenges. Eventually, instantaneous vector maps from PIV measurements are presented, where the dissipative small scale structures are resolved.

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Conference proceedings

conference paper

(c) 2013 Fiscaletti, D.; Elsinga, G.E.; Westerweel, J.