Simulation of the Uncertainties propagation in the measurement of the scattering matrix of a duct containing porous material

Abstract

The objective of a theoretical simulation of an experiment is the identification of the experience parameters which are the most sensitive to errors to take them into account during the measurement and to reduce their corresponding errors. In this study, a simulation of the experiment procedure of measurement of the scattering matrix and the acoustic power attenuation of a duct element containing porous material is presented. The influence of the errors of measurement parameters like the separation distance, the length of the porous material and the modulus of the incident pressure on the measured quantities (scattering matrix coefficients and the acoustic power attenuation) is evaluated using the Monte Carlo technique. This method is considered as a benchmark for examining uncertainty diffusion on theoretical methods. The results of the uncertainty simulation are used to determine the 95% confidence intervals and the maximum and minimum errors for each measured parameter. The obtained results show that errors on the estimation of the length of the porous material has a great influence on the transmission and reflection coefficients as well as the acoustic power attenuation of the studied duct. For the other parameters, their effects are negligible.