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Experiments in Fluids

, Volume 35, Issue 5, pp 408–421 | Cite as

Analysis and treatment of errors due to high velocity gradients in particle image velocimetry

Original Paper

Abstract

This paper deals with errors occurring in two-dimensional cross-correlation particle image velocimetry (PIV) algorithms (with window shifting), when high velocity gradients are present. A first bias error is due to the difference between the Lagrangian displacement of a particle and the real velocity. This error is calculated theoretically as a function of the velocity gradients, and is shown to reach values up to 1 pixel if only one window is translated. However, it becomes negligible when both windows are shifted in a symmetric way. A second error source is linked to the image pattern deformation, which decreases the height of the correlation peaks. In order to reduce this effect, the windows are deformed according to the velocity gradients in an iterative process. The problem of finding a sufficiently reliable starting point for the iteration is solved by applying a Gaussian filter to the images for the first correlation. Tests of a PIV algorithm based on these techniques are performed, showing their efficiency, and allowing the determination of an optimum time separation between images for a given velocity field. An application of the new algorithm to experimental particle images containing concentrated vortices is shown.

Keywords

Velocity Field Particle Image Velocimetry Velocity Gradient Correlation Peak Particle Displacement 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. Adrian RJ (1988) Statistical properties of particle image velocimetry measurements in turbulent flow. In: Adrian RJ et al. (eds) Laser anemometry in fluid mechanics—III. LADOAN Instituto Superior Tecnico, Lisbon, pp 115–129Google Scholar
  2. Adrian RJ (1991) Particle-imaging techniques for experimental fluid mechanics. Annu Rev Fluid Mech 23:261–604CrossRefGoogle Scholar
  3. Fincham A, Delerce G (2000) Advanced optimization of correlation imaging velocimetry algorithms. Exp Fluids [Suppl] 29:S13–S22Google Scholar
  4. Fincham AM, Spedding GR (1997) Low cost, high resolution DPIV for measurement of turbulent fluid. Exp Fluids 23:449–462CrossRefGoogle Scholar
  5. Hart DP (2000) PIV error correction. Exp Fluids 29:13–22CrossRefGoogle Scholar
  6. Huang HT, Fiedler HE, Wang JJ (1993a) Limitation and improvement of PIV Part I: Limitation of conventional techniques due to deformation of image patterns. Exp Fluids 15:168–174Google Scholar
  7. Huang HT, Fiedler HE, Wang JJ (1993b) Limitation and improvement of PIV Part II: Particle image distortion, a novel technique. Exp Fluids 15:263–273Google Scholar
  8. Ishikawa M, Murai Y, Wada A, Iguchi M (2000) A novel algorithm for particle tracking velocimetry using the velocity gradient tensor. Exp Fluids 29:519–531CrossRefGoogle Scholar
  9. Jambunathan K, Ju XY, Dobbins BN, Ashforth-Frost S (1995) An improved cross correlation technique for particle image velocimetry. Meas Sci Technol 6:507–514Google Scholar
  10. Leweke T, Meunier P, Laporte F, Darracq D (2001) Controlled interactions of co-rotating vortices. In: Bütefisch K et al (eds) 3rd ONERA-DLR Aerospace Symposium (ODAS 2001). ONERA, Paris, paper S2-3Google Scholar
  11. Lin HJ, Perlin M (1998) Improved methods for thin surface boundary layer investigations. Exp Fluids 25:431–444Google Scholar
  12. Meunier P, Leweke T (2001) Three-dimensional instability during vortex merging. Phys Fluids 13:2747–2750Google Scholar
  13. Meunier P, Leweke T (2003) Elliptic instability of a co-rotating vortex pair. J Fluid Mech in pressGoogle Scholar
  14. Meunier P, Ehrenstein U, Leweke T, Rossi M (2002) A merging criterion for two-dimensional co-rotating vortices. Phys Fluids 14:2757–2766Google Scholar
  15. Nogueira J, Lecuona A, Rodriguez PA (1999) Local field correction PIV: on the increase of accuracy of digital PIV systems. Exp Fluids 27:107–116CrossRefGoogle Scholar
  16. Raffel M, Willert CE, Kompenhans J (1998) Particle image velocimetry: a practical guide. Springer, Berlin Heidelberg New YorkGoogle Scholar
  17. Scarano F, Riethmuller ML (1998) Advances in iterative multigrid PIV image processing. Exp Fluids [Suppl] 29:S51–S60Google Scholar
  18. Wereley ST, Meinhart CD (2001) Second-order accurate particle image velocimetry. Exp Fluids 31:258–268CrossRefGoogle Scholar
  19. Westerweel J (1993) Digital particle image velocimetry. PhD Thesis, Technical University Delft.Google Scholar
  20. Willert CE, Gharib M (1991) Digital particle image velocimetry. Exp Fluids 10:181–193Google Scholar

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  1. 1.Institut de Recherche sur les Phénomènes Hors EquilibreUMR 6594 CNRS/Universités Aix-Marseille I & IIMarseille Cédex 13France

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