HIGH ACCURACY COMPACT SCHEMES AND GIBB'S PHENOMENON

By T.K. Sengupta, G. Ganeriwal and A. Dipankar

Abstract

Compact difference schemes have been investigated for their ability to capture discontinuities. A new proposed scheme (Sengupta, Ganeriwal and De (2003), J. Comp. Phys., 192(2), 677 is compared with another from the literature Zhong (1998), J. Comp. Phys., 144, 622 that was developed for hypersonic transitional flows for their property related to spectral resolution and numerical stability. Solution of the linear convection equation is obtained that requires capturing discontinuities. We have also studied the performance of the new scheme in capturing discontinuous solution for the Burgers equation. A very simple but an effective method is proposed here in early diagnosis for evanascent discontinuities. At the discontinuity, we switch to a third order one-sided stencil, thereby retaining the high accuracy of solution. This produces solution with vastly reduced Gibbs' phenomenon of the solution. The essential causes behind Gibbs' phenomenon is also explained.