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Investigations of turbulent mixing regions


Kuethe, Arnold M. (1933) Investigations of turbulent mixing regions. Dissertation (Ph.D.), California Institute of Technology.


The turbulent mixing of two jets of fluid of the same density is investigated theoretically by means of Prandtl's theory of turbulence and the results compared with experiment. The mixing length is assumed proportional to the breadth of the mixing region with a proportionality constant which is the only empirical constant in the theory.

In Part II a solution obtained by Tollmien for the mixing region of a plane jet, in which he considers the fluid bounding the jet at rest, is extended to the general case of the mixing of two streams of different velocities separated initially by a plane surface. Distributions of the tangential and normal velocities in the mixing region are given.

Part III deals with the turbulent mixing region surrounding axially symmetric jet issuing into fluid at rest. The problem is solved, as far as the core of potential flow extends, by the application of a new method of approximation directly to the partial differential equation of motion. The velocity field, as determined by a second approximation to the velocity profiles, is given. An extension of the method of solution, applicable to problems in which the velocity profiles differ widely, is mentioned.

In Part IV the empirical constant occurring in the assumption for the mixing length is evaluated. Velocity profiles in the mixing region of an axially symmetric jet were measured by means of a pitot tube and good agreement is found between theory and experiment.

Finally, some measurements or the velocity fluctuations, made by means of the hot-wire anemometer, are given.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Von Kármán, Theodore (advisor)
  • Tollmien, Walter (advisor)
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1933
Record Number:CaltechETD:etd-04222008-113609
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1459
Deposited By: Imported from ETD-db
Deposited On:24 Apr 2008
Last Modified:26 Dec 2012 02:38

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PDF (Kuethe_am_1933.pdf) - Final Version
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