A COMPARISON OF SCALAR SINGULAR FINITE-ELEMENTS APPLIED TO THE ANALYSIS OF HOMOGENEOUS WAVE-GUIDES WITH SHARP EDGES

When we solve the wave equation by the finite element method, the orde r of convergence and the accuracy of the solution are reduced by the p resence of sharp edges. The employment of singular elements improves t he solution and allows us to reduce the cost of computation. In this p aper, three types of scalar singular finite elements with the capacity to handle singularities in the derivative, and which have previously been applied to mechanical problems, are examined, together with stand ard elements, in the context of homogeneous waveguide analysis. We sol ve two examples of homogeneous waveguides showing the different behavi our of the singular elements and obtaining information on the order of convergence and the approximation of the gradient of the unknown func tion. (C) 1997 John Wiley & Sons, Ltd.