A time-domain implementation of surface acoustic impedance condition with and without flow


Özyörük Y., Long L. N.

2nd AIAA/CEAS Aeroacoustics Conference, 1996, Pennsylvania, United States Of America, 6 - 08 May 1996 identifier

  • Publication Type: Conference Paper / Full Text
  • Volume:
  • Doi Number: 10.2514/6.1996-1663
  • City: Pennsylvania
  • Country: United States Of America

Abstract

© 1996, American Institute of Aeronautics and Astronautics, Inc.The impedance condition in computational aeroacoustic applications is required in order to model acoustically treated walls. The application of this condition in time-domain methods, however, is extremely difficult because of the convolutions involved. In this paper, a timedomain method is developed which overcomes the computational difficulties associated with these convolutions. This method builds on the z-transform from control and signal processing theory and the z-domain model of the impedance. The idea of using the z-domain operations originates from the computational electromagnetics community. When the impedance is expressed in the zdomain with a rational function, the inverse z-transform of the impedance condition results in only infinite impulse response type, digital, recursive filter operations. These operations, unlike convolutions, require only limited past-time knowledge of the acoustic pressures and velocities on the surface. One- and two-dimensional example problems with and without flow indicate that the method promises success for aeroacoustic applications.