Acoustic power¯ow measurement in a
thermoacoustic resonator by means of laser
Doppler anemometry (L.D.A.) and
H. Bailliet a,*, P. Lotton a, M. Bruneau a, V. Gusev b,
J.C. ValieÁ re a, B. Gazengel a
aLaboratoire d'Acoustique de l'UniversiteÂ du Maine, UMR-CNRS 6613, IAM,
Univ. du Maine, av. O. Messiaen, 72085 Le Mans Cedex 9, France
bLaboratoire de I'Etat CondenseÂ de la FaculteÂ des Sciences, UPRESA-CNRS 6087,
av. O. Messiaen, 72085 Le Mans Cedex 9, France
Received 6 April 1999; received in revised form 30 June 1999; accepted 17 August 1999
Acoustic power¯ow measurements in the resonator of a thermoacoustic refrigerator are
described. The technique of measurement is based on particle velocity measurement by laser
Doppler anemometry (L.D.A.) together with microphonic acoustic pressure measurement.
The calibration procedure is explained and results of measurements are compared with ana-
lytical results. The L.D.A. technique permits the measurement of acoustic power¯ow at
almost any position and for almost any working frequency in the resonator of thermoacoustic
devices. # 2000 Elsevier Science Ltd. All rights reserved.
Keywords: Acoustic power¯ow; laser Doppler anemometry; thermoacoustics; sound measurement
The thermoacoustic process is based on the eects that occur in the thermal
boundary layers associated with an acoustically oscillating¯uid close to a rigid wall.
These eects are used to convert acoustic work¯ow into heat¯ow (thermoacoustic
refrigerator) or the contrary (thermoacoustic prime mover) (e.g. ). In the case of
thermoacoustic refrigerators, this process involves a high amplitude resonant
Applied Acoustics 60 (2000) 1±11
0003-682X/00/$ - see front matter # 2000 Elsevier Science Ltd. All rights reserved.
PII : S0003-682X(99)00046-8
* Corresponding author. Tel.: +33-2-4383-3270; fax: +33-2-4383-3520.
E-mail address: email@example.com (P. Lotton).
acoustic ®eld inside a¯uid-®lled resonant cavity, that is due to