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Experiments on pulsation effects in turbulent flows, Part I: Investigation on Simple Shear Flows

Shahidinejad, S ; Sharif University of Technology | 2003

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  1. Type of Document: Article
  2. Publisher: Sharif University of Technology , 2003
  3. Abstract:
  4. This article describes the results of experimental observations in pulsating Simple Shear Flows (SSF). A uniform-mean-gradient shear flow was generated within the test section of an open circuit wind tunnel. Transverse arrays of honeycomb channels with differing resistances were used to generate shear flow at low shear rates (less than 20 s-1). A set of rotating vanes pulsated the flow field at 8.5 Hz and 18 Hz. Instantaneous velocity was measured by employing a two-component hot wire anemometry technique. The experimental credibility of the facility was established in stationary SSF. In pulsating flows the pulsation effects on mean shear rate, the kinetic energy of turbulence, Reynolds stresses and the probability density of stream-wise velocity fluctuations were studied. It was found that deviation from stationary turbulence with pulsation at 8.5 Hz was more significant than that at 18 Hz. The modified form of the governing equations for pulsating flows was derived. The emphasis of the analysis was placed on the production and dissipation mechanisms in pulsating SSF. The results are discussed in connection with the modified equations and physically plausible explanations are offered to interpret the laboratory observations. It is concluded that the anisotropic dissipation mechanism may be responsible for the observed experimental results
  5. Keywords:
  6. Pulsation ; Turbulent flow ; Shear flow
  7. Source: Scientia Iranica ; Volume 10, Issue 2 , 2003 , Pages 238-247 ; 10263098 (ISSN)
  8. URL: https://www.sid.ir/en/Journal/ViewPaper.aspx?ID=95049