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MAPPED INFINITE WAVE ENVELOPE ELEMENTS FOR ACOUSTIC RADIATION IN A UNIFORMLY MOVING MEDIUM

✍ Scribed by WALTER EVERSMAN


Publisher
Elsevier Science
Year
1999
Tongue
English
Weight
309 KB
Volume
224
Category
Article
ISSN
0022-460X

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✦ Synopsis


Variable order mapped in"nite wave envelope elements are developed for "nite-element modelling (FEM) of acoustic radiation in a uniformly moving medium. These elements can be used as a non-re#ecting boundary condition for computations on an in"nite domain in which a radiating body is immersed in a moving medium which is essentially undisturbed outside of the near "eld. An additional result of this study shows that the mapped wave envelope elements provide a boundary condition equivalent to sti!ness, mass, and damping matrices appended to the inner mesh. By choosing the transition between the standard FEM mesh and the mapped in"nite wave envelope as a surface of constant phase the mass matrix is caused to vanish identically. This has implications for transient FEM modelling of acoustic radiation. A demonstration of the characteristics of mapped in"nite wave envelope elements is given in the context of acoustic radiation from a turbofan inlet for which benchmark results are known.