Effects of the finite circular baffle size on the sound power measurement
- Publication Type:
- Conference Proceeding
- INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet, 2017, 2017-January
- Issue Date:
© 2017 Institute of Noise Control Engineering. All Rights Reserved. Sound power measurements are often required in noise control. According to ISO 3745, the reflecting plane shall exceed at least 1/4 wavelength and no less than 0.75 m beyond the measurement surface when the sound power level is measured with microphones at a hemispherical surface in an anechoic chamber. However, the effect of the baffle size on the measured sound power level is still not clear. This paper develops an analytical model to calculate the scattering sound from a monopole noise source above a finite circular baffle. The measurement accuracy by using 10 microphones on a hemispherical surface centered at the baffle center is analyzed based on the scattering model in the spheroidal oblate coordinate system. The correction terms due to the baffle scattering are given for the monopole source at different heights. Numerical simulations are also conducted to validate the proposed model and the specified correction terms.
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