Experiments in Fluids

, Volume 8, Issue 3–4, pp 153–160 | Cite as

Distribution of turbulence energy dissipation rates in a Rushton turbine stirred mixer

  • H. Wu
  • G. K. Patterson
  • M. Van Doorn


An approximate method of measuring the turbulence energy dissipation rate (ɛ) in mixers by use of laser-Doppler measurements of the velocity autocorrelation and turbulence energy was successful in yielding remarkably consistent values. The necessary corrections for periodic, non-dissipative velocity fluctuations were made by an autocorrelation method. Two modes of periodic fluctuation were found to be significant. Transformation of the corrected autocorrelations yielded completely normal turbulence energy spectra.

List of symbols


fluctuating concentration, C−C


impeller diameter


molecular diffusivity


autocorrelation function

E1 (n)

one-dimensional energy spectrum function


turbulence energy (=q)


macroscale of segregation


integral velocity scale


impeller rotation rate


Schmidt number (v/D)


turbulence energy (=k)


radial distance from impeller shaft


impeller radius


tank diameter

U, V, W

velocity in x, y, z directions

u, v, w

velocity fluctuations

ur, uθ, uz

fluctuating velocities in radial, tangential, and axial (shaft) directions

Ur, Uθ, Uz



axial distance from impeller disk


tank height


turbulence energy dissipation rate




time delay


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Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • H. Wu
    • 1
  • G. K. Patterson
    • 1
  • M. Van Doorn
    • 1
  1. 1.Dept. of Chemical EngineeringUniversity of ArizonaTucsonUSA

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