An Efficient Semianalytical Method for Hypersingularity Treatment Over Curved Patches

Selcuk, G.
Koç, Seyit Sencer
In this communication, we propose an efficient method to evaluate hypersingular integrals defined on curved surfaces. First an exact expression for hypersingular kernel is derived by projecting the integral on curvilinear element on a flat surface. Next singularity subtraction employed, where the singular core is hypersingular and the remaining part is weakly singular. The singular core is evaluated analytically using finite part interpretation and the remaining weakly singular part is evaluated numerically using Gauss-Legendre quadrature rules. By numerical experiments we have shown that the convergence rate of the purposed method is quite high even for few number of quadrature nodes. Accuracies over ten digits are obtained for relatively large and highly curved surfaces, which may cover entire domain of local corrections in Nystrom method.


Evaluation of Hypersingular Integrals on Non-planar Surfaces
Selcuk, Gokhun; Koç, Seyit Sencer (2014-05-16)
Solving electric field integral equation (EFIE) with Nystrom method requires accurate evaluation of hypersingular surface integrals since this method does not use divergence conforming basis and testing functions. The success of the method also depends on accurate representation of non-planar characteristics of the scattering object. In this study Hadamard finite part interpretation is used to evaluate hypersingular integrals over non-planar surfaces, which are represented by their Taylor series expansions....
Evaluation of Hypersingular Integrals on Curvilinear Surface Elements
Selcuk, Gokhun; Koç, Seyit Sencer (2016-04-15)
In this study finite part integrals are utilized for evaluation of hypersingular and nearly-hypersingular surface integrals on curvilinear elements. These integrals are related to the second derivative of the free space Green' function and arise in the solution of electric field integral equation (EFIE) via locally corrected Nystriim (LCN) method. The curvilinear elements are represented by the Taylor series expansion of the surface function around the observation point. The hypersingular integral, defined ...
A Novel Approach for the Efficient Computation of 1-D and 2-D Summations
Karabulut, E. Pinar; ERTÜRK, VAKUR BEHÇET; Alatan, Lale; Karan, S.; Alisan, Burak; Aksun, M. I. (2016-03-01)
A novel computational method is proposed to evaluate 1-D and 2-D summations and integrals which are relatively difficult to compute numerically. The method is based on applying a subspace algorithm to the samples of partial sums and approximating them in terms of complex exponentials. For a convergent summation, the residue of the exponential term with zero complex pole of this approximation corresponds to the result of the summation. Since the procedure requires the evaluation of relatively small number of...
TANRIKULU, O; KURAN, B; Özgüven, Hasan Nevzat; IMREGUN, M (1993-07-01)
The dynamic response of multiple-degree-of-freedom nonlinear structures is usually determined by numerical integration of the equations of motion, an approach which is computationally very expensive for steady-state response analysis of large structures. In this paper, an alternative semianalytical quasilinear method based on the describing function formulation is proposed for the harmonic response analysis of structures with symmetrical nonlinearities. The equations of motion are converted to a set of nonl...
Improving the Accuracy of MFIE and CFIE by Using Numerically Designed Testing Functions
Karaosmanoglu, Bariscan; Ergül, Özgür Salih (2016-07-01)
We present a novel approach for improving the accuracy of the magnetic-field integral equation (MFIE) and the combined-field integral equation (CFIE) by using numerically designed testing functions. The compatibility of the MFIE and CFIE systems with the corresponding one derived from the electric-field integral equation (EFIE) is used to determine testing weights in given templates of testing directions. The designed testing functions lead to more accurate solutions in comparison to the standard discretiza...
Citation Formats
G. Selcuk and S. S. Koç, “An Efficient Semianalytical Method for Hypersingularity Treatment Over Curved Patches,” IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, pp. 2740–2744, 2017, Accessed: 00, 2020. [Online]. Available: