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Investigation of Turbulent Flow in a Two-Dimensional Channel


Laufer, John (1948) Investigation of Turbulent Flow in a Two-Dimensional Channel. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/6ZYC-HJ88.


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A detailed exploration of the field of mean and fluctuating quantities in a two-dimensional turbulent channel flow is presented. The measurements were repeated at three Reynolds numbers, 1.23 x 10⁵, 3.08 x 10⁵ and 6.16 x 10⁵, based on the half width of the channel and the maximum velocity. A channel of 5" width and 12:1 aspect ratio was used for the investigation.

Mean speed and axial fluctuation measurements were made well within the laminar sublayer. The semi-theoretical predictions concerning the extent of the laminar sublayer were confirmed. It was found that the viscosity has a more profound influence on the fluctuations than on the mean velocity, the region of influence being approximately four times as wide.

Fluctuations perpendicular to the flow direction v', w' and the correlation coefficient [...] were measured, and the turbulent shear distribution calculated. Shear calculations from independent methods using the measured velocity gradient at the wall and pressure gradient along the channel furnished a good check on the values of the shearing stress in all cases with the exception of the highest Reynolds number where Τ obtained from the fluctuation measurements is approximately 25% lower. All mean fluctuating quantities were found to decrease with increasing Reynolds number. Measurements of the scales Ly, Lz and micro-scales of turbulence λy, λz across the channel are presented and their variation with Reynolds number is discussed. Using a new technique, values for λx were obtained; a method for estimating Lx is also given.

The energy balance in the turbulent flow field was calculated from the measured quantities. From this calculation it is possible to give a descriptive picture of turbulent energy diffusion in the center portion of the channel cross-section.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Aeronautics and Physics)
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Minor Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Liepmann, Hans Wolfgang
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1948
Record Number:CaltechETD:etd-09152005-133021
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3549
Deposited By: Imported from ETD-db
Deposited On:16 Sep 2005
Last Modified:21 Mar 2023 23:52

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