A Method of Measuring Acoustic Wave Attenuation in the Laboratory
Name
1987.16 Tang et al.pdf
Size
573.55 KB
Format
Adobe PDF
Checksum (MD5)
5ab12db719913c44afe378addc3bae72
Author(s)
Tang, X. M.
Toksoz, M. N.
Tarif, P.
Date Issued
1987
Publisher
Massachusetts Institute of Technology. Earth Resources Laboratory
Series/Report no.
Earth Resources Laboratory Industry Consortia Annual Report;1987-16
Abstract
The measurement of attenuation is performed by directly determining the attenuation
operator (or the impulse response of the medium) in the time domain. In this way,
it is possible to separate the attenuation operator from other non-attenuation effects,
e.g. reflections. The Wiener filtering technique, or the damped least-squares, is used to
calculate the attenuation operator. For the damped least squares, we have corrected for
the effect due to the addition of the damping constant using a perturbation method.
Numerical tests are carried out to illustrate the technique.
The geometric beam spreading of ultrasonic waves generated by a source of finite
size can strongly affect the result of attenuation measurements. Corrections are made
by equating the received signal to the average pressure over the receiver surface.
The technique is used to measure ultrasonic attenuation in water, glycerol and mud.
The measurement in water offers a test of the corrections made for the geometric beam
spreading. The measurement in glycerol and mud shows that, in the frequency range
of 0.2-1.5 MHz, the attenuation of glycerol increases rapidly with frequency, whereas
the attenuation of mud is proportional to frequency, exhibiting a constant Q behavior.
The measurements show that the technique used here is an effective approach to the
measurement of attenuation.
Persistent DSpace Link
