A High Accuracy Nonconforming Finite Element Scheme for Helmholtz Transmission Eigenvalue Problem

In this paper, we consider a cubic H-2 nonconforming finite element scheme B-h0(3) which does not correspond to a locally defined finite element with Ciarlet's triple but admit a set of local basis functions. For the first time, we deduce and write out the expression of basis functions explicitly. Distinguished from the most nonconforming finite element methods, (delta Delta(h)., Delta(h).) with non-constant coefficient delta > 0 is coercive on the nonconforming B-h0(3) space which makes it robust for numerical discretization. For fourth order eigenvalue problem, the B-h0(3) scheme can provide O(h(2)) approximation for the eigenspace in energy norm and O(h(4)) approximation for the eigenvalues. We test the B-h0(3) scheme on the vary-coefficient bi-Laplace source and eigenvalue problem, further, transmission eigenvalue problem. Finally, numerical examples are presented to demonstrate the effectiveness of the proposed scheme.