A spectral boundary integral method for computing the effect of locally and non-locally reacting liners in flow duct applications

摘要

In order to predict acoustic performances of duct liners, a special boundary integral method is presented which allows to handle locally or non-locally reacting liners. Using a tailored Green's function for hard wall circular ducts containing uniform mean flow, the numerical technique only requires the discretization of the acoustic velocity potential on the duct surface. The method is developed and applied to the prediction of the transmitted field in circular ducts lined with perforated sheets with partition spacing in the air backing. Comparisons with finite element results show that the proposed method allows accurate results for a relatively modest computational cost. Influence of the mean flow in the central airway, the dimensions of the cavity as well as the nature of the incident field on acoustic performances are also shown and discussed.