The present work proposed a new method for the modeling by the finite element
method of the acoustic propagation problems in infinite axisymmetric
cylindrical guides lined with locally reacting absorbent materials without
flow. The method deals with the development of an efficient transparent
boundary condition based on DtN operators. The method developed in this
study is successfully applied to a straight axisymmetric lined guide by imposing
a mode on one of the artificial boundaries of the truncated guide. The results
are in good agreement with analytical solutions. Applying the method
for a non-uniform axisymmetric lined guide which is a complex case, proved
its effectiveness and the results compared to those of PML layers are in very
good agreement.

DtN Operator Axisymmetric Cylindrical Guides Finite Element Method