Direction-Adaptive Nonreflecting Boundary Conditions

✍ Scribed by Paolo Luchini; Renato Tognaccini

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 559 KB
• Volume: 128
• Category: Article
• ISSN: 0021-9991
• DOI: 10.1006/jcph.1996.0199

✦ Synopsis

Presented in this work is a nonlinear adaptive nonreflecting boundary condition (NRBC) that, when compared with classical local NRBCs, further reduces the wave reflection error at far fields in the numerical simulation of wave dominated problems. A nonlinear procedure can considerably improve the accuracy of NRBCs even if the problem itself is linear as in the case of the 2D wave equation. In fact the first-and second-order NRBCs of Engquist and Majda can be modified by adding proper weights to the coefficients of the difference equations. The weights are adaptively determined in such a way that the angle of complete absorption is locally coincident with the outgoing wave direction. The theoretical reflection coefficients and the numerical experiments show that a considerable reduction of the numerical error due to wave reflections is achieved by applying the present adaptive algorithm.