Use of Improved Far -Field Boundary Conditions to Compute External Flows on Reduced Domains

Mantle, William Joseph

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https://hdl.handle.net/2142/84013 Copy

Description

Title

Use of Improved Far -Field Boundary Conditions to Compute External Flows on Reduced Domains

Author(s)

Mantle, William Joseph

Issue Date

2000

Doctoral Committee Chair(s)

Pearlstein, Arne J.

Department of Study

Mechanical Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Applied Mechanics

Language

eng

Abstract

We have also used this computational approach to study, for the first time, flow past a convex axisymmetric body formed by a finite paraboloid with a paraboloidal surface closing the aperture. Converged flows were computed for three different aspect ratios up to a Reynolds number (Re) of 200. For sufficiently small Re, there is no separation. For an intermediate range of Re, the separation point moves from the rear stagnation point towards the edge of the body as Re increases. Beyond some Re, the computed separation circle lies between the edge and nearest grid point, for all grid spacings considered. The length of the separated flow region varies approximately with a fractional power of the logarithm of the Reynolds number. The computational advantages of the present approach are demonstrated by comparing memory usage and runtime for solutions of comparable accuracy. When the system of nonlinear algebraic equations is solved by Newton iteration, memory usage and runtime are reduced by about 70% compared to computations using Neumann and free-stream Dirichlet boundary conditions.

Graduation Semester

2000

Type of Resource

text

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http://hdl.handle.net/2142/84013

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