A hybrid-Trefftz finite element model for Helmholtz problem.

In this paper, a hybrid-Trefftz four-node quadrilateral element model is formulated for Helmholtz problem. In this model, two Helmholtz approximations are defined. The first approximation is obtained by nodal interpolation, and the second approximation is truncated from a Trefftz solution set. A hybrid variational functional is employed to enforce the equality of and other necessary conditions on the two approximations. From the numerical tests, it can be seen that the hybrid model is markedly more accurate than the conventional finite element model. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]