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An interactive boundary layer modelling methodology for aerodynamic flows

Dissertation (MEng)--University of Pretoria, 2012.

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Other Authors: Oxtoby, Oliver F.
Format: Thesis
Published: University of Pretoria 2013
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access_status_str Open Access
author2 Oxtoby, Oliver F.
author_browse Oxtoby, Oliver F.
author_facet Oxtoby, Oliver F.
collection Thesis
dc_rights_str_mv © 2011, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria
description Dissertation (MEng)--University of Pretoria, 2012.
format Thesis
id oai:repository.up.ac.za:2263/25872
institution University of Pretoria (South Africa)
last_indexed 2026-06-10T12:37:29.889Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2013
publishDateRange 2013
publishDateSort 2013
publisher University of Pretoria
publisherStr University of Pretoria
record_format dspace
source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/25872 An interactive boundary layer modelling methodology for aerodynamic flows Oxtoby, Oliver F. Meyer, Josua P. Malan, A.G. lekepe@gmail.com Smith, Lelanie Boundary layer Two-integral method Coupling Auxiliary velocity Mesh movement algorithm Displacement thickness UCTD Dissertation (MEng)--University of Pretoria, 2012. Computational fluid dynamics (CFD) simulation is a computational tool for exploring flow applications in science and technology. Of central importance in many flow scenarios is the accurate modelling of the boundary layer phenomenon. This is particularly true in the aerospace industry, where it is central to the prediction of drag. Modern CFD codes as applied to modelling aerodynamic flows have to be fast and efficient in order to model complex realistic geometries. When considering viscous flows, the boundary layer typically requires the largest part of computational resources. To simulate boundary layer flow with most current CFD codes, requires extremely fine mesh spacing normal to the wall and is consequently computationally very expensive. Boundary layer modelling approaches offer considerable computational cost savings. One boundary layer method which proved to be very accurate is the two-integral method of Drela (1985). Coupling the boundary layer solution to inviscid external flow, however, is a challenge due to the Goldstein singularity, which occurs as separation is approached. This research proposed to develop a new method to couple Drela‟s two-integral equations to a generic outer flow solver in an iterative fashion. The study introduced an auxiliary equation, which was solved along with the displacement thickness to overcome the Goldstein singularity without the need to solve the entire flow domain simultaneously. In this work, the incompressible Navier-Stokes equations were used for the outer flow. In the majority of previous studies, the boundary layer thickness was simulated using a wall transpiration boundary condition at the interface between viscous and inviscid flows. This boundary condition was inherently non-physical since it added extra mass into the system to simulate the effects of the boundary layer. Here, this drawback was circumvented by the use of a mesh movement algorithm to shift the surface of the body outward without regridding the entire mesh. This replaced the transpiration boundary condition. The results obtained show that accurate modelling is possible for laminar incompressible flow. The predicted solutions obtained compare well with similarity solutions in the case of flat and inclined plates, and with the results of a NACA0012 airfoil produced by the validated XFOIL code (Drela and Youngren, 2001). Copyright Mechanical and Aeronautical Engineering unrestricted 2013-09-07T01:05:10Z 2012-06-29 2013-09-07T01:05:10Z 2012-04-23 2012-06-29 2012-06-26 Dissertation Smith, L 2011, An interactive boundary layer modelling methodology for aerodynamic flows, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/25872 > E12/4/428/gm http://hdl.handle.net/2263/25872 http://upetd.up.ac.za/thesis/available/etd-06262012-100134/ © 2011, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria application/pdf University of Pretoria
spellingShingle Boundary layer
Two-integral method
Coupling
Auxiliary velocity
Mesh movement algorithm
Displacement thickness
UCTD
An interactive boundary layer modelling methodology for aerodynamic flows
title An interactive boundary layer modelling methodology for aerodynamic flows
title_full An interactive boundary layer modelling methodology for aerodynamic flows
title_fullStr An interactive boundary layer modelling methodology for aerodynamic flows
title_full_unstemmed An interactive boundary layer modelling methodology for aerodynamic flows
title_short An interactive boundary layer modelling methodology for aerodynamic flows
title_sort interactive boundary layer modelling methodology for aerodynamic flows
topic Boundary layer
Two-integral method
Coupling
Auxiliary velocity
Mesh movement algorithm
Displacement thickness
UCTD
url http://hdl.handle.net/2263/25872
http://upetd.up.ac.za/thesis/available/etd-06262012-100134/