Reflections on the nonlinear equation of state in rock based on experiment

Journal Article · Wed Nov 01 04:00:00 EST 1995 · Journal of the Acoustical Society of America

DOI:https://doi.org/10.1121/1.414233· OSTI ID:122301

TenCate, J A ^[1]

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1. EES-4 MS D443, Los Alamos Natl. Lab., Los Alamos, NM 87545 (United States)

Measurements were made of the propagation of 1-D nonlinear waves (i.e., Young`s mode) in a bar of Berea sandstone 3.8 cm in diameter and 1.8 m long. Both waveforms (time domain) and spectra (frequency domain) were measured. The experimental results were then compared with waveforms calculated from a numerical scheme based on the simple wave solution for 1-D waves in rock using a classical nonlinear equation of state. The numerical solution is written in MATLAB and runs quickly on a small personal computer. Attenuation was added by propagating the waveform a small distance, transforming the waveform into the frequency domain, and applying the attenuation, and then transforming back into the time domain and propagating the new waveform. The same method was applied earlier for nonlinear propagation of a sound wave in a tube of air by Pestorius and Blackstock. The experiments and simulations clearly demonstrate that a classical nonlinear equation of state is incomplete or inappropriate for describing or modeling nonlinear propagation in sandstone. Results from another model (Van Den Abeele, paper 2aPA8) suggest the same conclusions. [Work supported by OBES/DOE through the University of California.]

• Sponsoring Organization: USDOE
• OSTI ID: 122301
• Journal Information: Journal of the Acoustical Society of America, Journal Name: Journal of the Acoustical Society of America Journal Issue: 5 Vol. 98; ISSN 0001-4966; ISSN JASMAN
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
EQUATIONS OF STATE
MATHEMATICAL MODELS
NONLINEAR PROBLEMS
NUMERICAL SOLUTION
ROCKS
WAVE FORMS
WAVE PROPAGATION