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Investigation of an Instability Phenomena Occurring in Supersonic Diffusors


Stoolman, Leo (1953) Investigation of an Instability Phenomena Occurring in Supersonic Diffusors. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/EG52-8V58.


Experimental investigations of supersonic normal shock type diffusors have shown the existence of self-excited oscillations that occur as the internal mass flow is reduced somewhat below its maximum value. There is a lower bound of free stream Mach number (of the order of 1.8) below which no instability could be observed. However, as free stream Mach number was increased above this lower bound, instability occurred at increasing values of the internal mass flow. Also, the frequency at instability was of the order of the natural frequency of the internal duct acting as organ pipe. First-order theoretical investigations of the above phenomena indicate that the instability may (in part) be interpreted as intrinsic, that is, independent of viscous effects at the duct inlet or within the diffusor. The fundamental cause of the instability is shown to be due to the nature of the oscillatory inlet flow conditions that occur as a consequence of the external compression from the shock wave to the inlet, and the type of reflections suffered at the shock wave by upstream traveling pressure waves.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Aeronautics and Mathematics)
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Minor Option:Mathematics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Nagamatsu, Henry T.
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1953
Additional Information:Title varies in 1953 Caltech Commencement program is: Stability of Supersonic Diffusers
Record Number:CaltechETD:etd-05122003-115303
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1737
Deposited By: Imported from ETD-db
Deposited On:13 May 2003
Last Modified:26 May 2023 18:55

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PDF (Stoolman_l_1953.pdf) - Final Version
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