Accession Number:

ADA314236

Title:

Parallel Newton-Krylov-Schwarz Algorithms for the Transonic Full Potential Equation.

Descriptive Note:

Contract rept.,

Corporate Author:

INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA

Report Date:

1996-05-01

Pagination or Media Count:

28.0

Abstract:

We study parallel two-level overlapping Schwarz algorithms for solving nonlinear finite element problems, in particular, for the full potential equation of aerodynamics discretized in two dimensions with bilinear elements. The overall algorithm, Newton-Krylov-Schwarz NKS, employs an inexact finite-difference Newton method and a Krylov space iterative method, with a twolevel overlapping Schwarz method as a preconditioner. We demonstrate that NKS, combined with a density upwinding continuation strategy for problems with weak shocks, is robust and economical for this class of mixed elliptic-hyperbolic nonlinear partial differential equations, with proper specification of several parameters. We study upwinding parameters, inner convergence tolerance, coarse grid density, subdomain overlap, and the level of fill-in in the incomplete factorization, and report their effect on numerical convergence rate, overall execution time, and parallel efficiency on a distributed-memory parallel computer.

Subject Categories:

  • Operations Research
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE