PROPAGATION OF SOUND IN A RARIFIED MAXWELLIAN GAS

Abstract

A study was made of the dispersion and attenuation of sound in a monoatomic gas with a density for which the mean free path is comparable to or exceeds the wave length of sound. The data on the propagation of sound in He at pressures of 1 mm and less required the solution of Boltzmann's complete transfer equation. Secular determinants of order 5, 8, 12, and 20 were evaluated in an effort to determine the phase velocity and attenuation coefficient. For each determinant order, the propagation constants were solved from the polynomial of the same degree representing the determinant; the polynomial roots were determined numerically. The results appeared to show that with a determinant of order 20, the computed values for the propagation constants is reliable for R greater than about 3, where R is proportional to lambda/L, the ratio of the wave length of sound to the mean free path. Graphical results are included for the determinant of order 8. Calculations are in progress for the determinant of order 30.

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Document Details

Document Type
Technical Report
Publication Date
Dec 23, 1953
Accession Number
AD0023611

Entities

People

  • G. L. Pekeris

Organizations

  • University of California, Los Angeles

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Acoustic Propagation
  • Applied Mathematics
  • Attenuation
  • Barometric Pressure
  • Boltzmann Equation
  • Coefficients
  • Collisions
  • Distribution Functions
  • Equations
  • Frequency
  • Integral Equations
  • Mean Free Path
  • Molecules
  • Phase Velocity
  • Polynomials
  • Power Series
  • Sound Waves

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Calculus or Mathematical Analysis
  • Fluid Dynamics.