Estimating Uncertainty in Computations of Two-Dimensional Separated Flows

Abstract

The present paper investigates sources of uncertainties in two- dimensional flow computations and presents methods for estimating them. Two sample problems are used for illustration. The following categories are explored in detail: (1) Uncertainty due to truncation error in numerical schemes; (2) Uncertainty due to discretization error; (3) Uncertainty due to outflow boundary conditions; (4) Uncertainty due to incomplete iterative convergence; (5) Uncertainty due to computational grid aspect ratio. The error estimates are based on requirements for internal consistencies in computed results. Therefore, they provide better judgement of the numerical solution integrity than comparisons to experimental data or 'benchmark' solutions whose reliability may sometimes be questionable. Ideally, both approaches should be employed. New results are presented on the optimum grid-cell aspect ratio for computational accuracy and efficiency.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1992
Accession Number
ADA261838

Entities

People

  • A. O. Demuren
  • R. V. Wilson

Organizations

  • National Aeronautics and Space Administration

Tags

Communities of Interest

  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Accuracy
  • Aspect Ratio
  • Boundaries
  • Boundary Layer
  • Computational Fluid Dynamics
  • Computational Science
  • Computations
  • Computers
  • Differential Equations
  • Engineering
  • Fluid Dynamics
  • Fluid Flow
  • Froude Number
  • Incompressible Flow
  • Laminar Flow
  • Shear Stresses
  • Two Dimensional

Readers

  • Computational Fluid Dynamics (CFD)
  • Finite Element Method (FEM) for solving Partial Differential Equations (PDEs)
  • Regression Analysis.