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Investigations on the Applications of the Hot Wire Anemometer for Turbulence Measurements


Knoblock, Frederick Delbridge (1939) Investigations on the Applications of the Hot Wire Anemometer for Turbulence Measurements. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/DKG6-T043.


The principle reasons for using the hot wire type of anemometer for turbulence measurements are outlined and some of the objectionable features limiting the applicability of the conventional type anemometer are pointed out. A brief historical background of the hot wire anemometer is followed by a consideration of various possibilities of improving the method of measuring the intensity of turbulence. This analysis purposes to show why such improvements can only be realized by a direct calibration of the hot wire’s response to velocity fluctuations. The consequent development of a new technique, referred to as the “Vibrator Method,” is then explained. A general discussion of the results of a series of investigations using the Vibrator method is then presented and includes: a comparison with the orthodox method; the response of the hot wire to periodic fluctuations relative to the validity of the theory of hot wire lag; an extension of the method to correlation measurements using two hot wires, and other applications. The paper concludes with a detailed description of various hot wire anemometer equipment which has been developed for use with the Vibrator method of measuring turbulence intensity.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Aeronautics)
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)
  • Millikan, Clark Blanchard (advisor)
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1939
Record Number:CaltechETD:etd-04252008-094935
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1502
Deposited By: Imported from ETD-db
Deposited On:25 Apr 2008
Last Modified:17 Aug 2023 00:00

Thesis Files

PDF (Knoblock_fd_1939.pdf) - Final Version
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