Accession Number:

ADA162334

Title:

Coupling Linearized Far-Field Boundary Conditions with Nonlinear Near-Field Solutions in Transonic Flow.

Descriptive Note:

Annual rept. 1 Jul 83-1 Feb 85,

Corporate Author:

BOEING COMMERCIAL AIRPLANE CO SEATTLE WA

Personal Author(s):

Report Date:

1985-02-01

Pagination or Media Count:

82.0

Abstract:

This investigation evaluated the feasibility of coupling linearized far-field finite differencing equations to reduce the size of grid networks required in present transonic flow calculations. A procedural change to an existing finite differencing program involved distributing sources on the solution interface boundary in order to develop the proper far-field outgoing wave boundary condition on a reduced size grid network. Validation of the modification procedure was established for zero thickness airfoils by comparing predicted two-dimensional results with results obtained from an exact procedure. A criterion based on the gradient of the flow field Mach number was developed for use in establishing the minimum size grid network necessary for accurate finite thickness unsteady loading predictions. Acceptable loading predictions were achieved for a nominal 51 gridsize reduction ratio with a 40 reduction in computer usage costs. Keywords Unsteady flow Transonic flow, Oscillating airfoils.

Subject Categories:

  • Numerical Mathematics
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE