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A Study of Active and Inactive Regions in Turbulence by Photon Correlation Spectroscopy

  • S. Chopra
  • S. K. P. Bhat
  • A. K. Razdan
Conference paper

Abstract

In a turbulent flow, it is the relative velocity V(R) between a pair of particles separated by a distance R, that is important rather than the instantaneous velocity v(t) at a point in the fluid1. If v1 and v2 are the velocities of a pair of particles seeded in the fluid with a separation R, then the velocity difference between them at the same instant of time will be V(R) = v1 − v2. By virtue of the Central limit theorem and Gaussian random nature of v1 and v2, the probability distribution function for the relative velocity fluctuations V(R) will have the form2
(1.1)
where ρ defines the correlation between v1 and v, and has a Lorentzian form. In our experiment, we calculated Pρ(V(R)) from the measurements of intensity autocorrela-tion function g(τ) behind a grid of mesh size 3 mm. using the equation2 given below and is displayed in Fig. 1.

Keywords

Decay Time Photon Correlation Spectroscopy Central Limit Theorem Probability Distribution Function Slit Width 
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.

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References

  1. 1.
    H.K. Pak and W.I. Goldburg, Phys. Fluids A5 (8), 2004 (1993).CrossRefGoogle Scholar
  2. 2.
    S.K.P. Bhat, S. Rai, A.K. Razdan and S. Chopra, Phy. Rev E 50 (6), 5127 (1994).CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1996

Authors and Affiliations

  • S. Chopra
    • 1
  • S. K. P. Bhat
    • 1
  • A. K. Razdan
    • 1
  1. 1.Department of PhysicsIndian Institute of TechnologyNew DelhiIndia

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