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Aerodynamic Dissipation

Published online by Cambridge University Press:  03 August 2017

H. E. Petschek
H. E. Petschek*
Affiliation:
AVCO Research Laboratory, Everett, Massachusetts

Extract

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Analyses of aerodynamic dissipation in ordinary un-ionized gases are all based upon the Navier-Stokes equations. These equations relate the rate of dissipation to the local gradients in velocity and temperature through the viscosity and heat conduction coefficients. Although it is true that in many flow situations the magnitude of the total dissipation in the gas does not depend on the magnitude of the viscosity coefficient, this coefficient does determine the minimum scale of variations observed in the gas and the form of the Navier-Stokes equations determines the type of phenomena which are observed on a small scale. In order to discuss dissipation in an ionized gas in the presence of a magnetic field, it is therefore necessary to re-examine the derivation of the basic flow equations. This paper attempts to do this for a case of a completely ionized gas and demonstrates that the basic microscopic dissipation mechanism is appreciably different. For example, it is shown that the minimum length in which the properties of the flow field can change noticeably is appreciably less than one mean free path.

Type
Part II: Theoretical Considerations on the Production and Dissipation of Velocity Fields in the Interstellar Medium
Information
Symposium - International Astronomical Union , Volume 8: Cosmical Gas Dynamics , July 1958 , pp. 966 - 974
Copyright
Copyright © American Physical Society 1958 

References

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∗ This experimental program is being carried out primarily by G. Sargent Janes.Google Scholar