Accurate acoustic power measurements with a high-intensity driver

Abstract

The design, construction, and calibration of a high-intensity acoustic driver apparatus with instrumentation for accurate measurements of dynamic pressure, volume velocity, and their relative phase are discussed. The acoustic power supplied by the driver can be determined from these measurements. The apparatus is capable of driving closed systems containing various gases at mean pressures ranging from 1–10 bar, at frequencies ranging from 400–700 Hz. Maximum acoustic powers attained are in excess of 13 W for systems with appropriate impedance. The accuracy of the power measurement is ±3% and the accuracy of the relative phase measurement is better than ±1°. The design of this apparatus can be simply optimized for other acoustic load impedances and frequencies.