Multi-objective optimization of transonic airfoils using variable-fidelity models, co-kriging surrogates, and design space reduction
dc.contributor.advisor | Leifur Leifsson | |
dc.contributor.author | Amrit, Anand | |
dc.contributor.department | Department of Aerospace Engineering | |
dc.date | 2018-08-11T12:06:10.000 | |
dc.date.accessioned | 2020-06-30T03:01:47Z | |
dc.date.available | 2020-06-30T03:01:47Z | |
dc.date.copyright | Fri Jan 01 00:00:00 UTC 2016 | |
dc.date.embargo | 2001-01-01 | |
dc.date.issued | 2016-01-01 | |
dc.description.abstract | <p>Computationally efficient constrained multi-objective design optimization of transonic airfoils is considered. The proposed methodology focuses on fixed-lift design aimed at finding the best possible trade-offs between the conflicting objectives. The algorithm exploits the surrogate-based optimization principle, variable-fidelity computational fluid dynamics (CFD) models, as well as auxiliary approximation surrogates (here, using kriging). The kriging models constructed within a reduced design space. The optimization process has three major stages: (i) design space reduction which involves the identification of the extreme points of the Pareto front through single-objective optimization, (ii) construction of the kriging model and an initial Pareto front generation using multi-objective evolutionary algorithm, and (iii) Pareto front refinement using co-kriging models. For the sake of computational efficiency, stages (i) and (ii) are realized at the level of low-fidelity CFD models. The proposed algorithm is applied to the multi-objective optimization of a transonic airfoil at a Mach number of 0.734 and a fixed lift coefficient of 0.824. The shape is parameterized with eight B-spline control points. The fluid flow is taken to be inviscid. The high-fidelity model solves the compressible Euler equations. The low-fidelity model is the same as the high-fidelity one, but with a coarser description and is much faster to execute. With the proposed approach, the entire Pareto front of the drag coefficient and the pitching moment coefficient is obtained using 100 low-fidelity samples and 3 high-fidelity model samples. This cost is not only considerably lower (up to two orders of magnitude) than the cost of direct high-fidelity mode optimization using metaheuristics without design space reduction, but, more importantly, renders multi-objective optimization of transonic airfoil shapes computationally tractable, even at the level of accurate CFD models.</p> | |
dc.format.mimetype | application/pdf | |
dc.identifier | archive/lib.dr.iastate.edu/etd/15148/ | |
dc.identifier.articleid | 6155 | |
dc.identifier.contextkey | 8928994 | |
dc.identifier.doi | https://doi.org/10.31274/etd-180810-4751 | |
dc.identifier.s3bucket | isulib-bepress-aws-west | |
dc.identifier.submissionpath | etd/15148 | |
dc.identifier.uri | https://dr.lib.iastate.edu/handle/20.500.12876/29332 | |
dc.language.iso | en | |
dc.source.bitstream | archive/lib.dr.iastate.edu/etd/15148/Amrit_iastate_0097M_15731.pdf|||Fri Jan 14 20:36:32 UTC 2022 | |
dc.subject.disciplines | Aerospace Engineering | |
dc.subject.keywords | Aerospace Engineering | |
dc.subject.keywords | design space reduction | |
dc.subject.keywords | optimization | |
dc.subject.keywords | space mapping | |
dc.subject.keywords | transonic | |
dc.title | Multi-objective optimization of transonic airfoils using variable-fidelity models, co-kriging surrogates, and design space reduction | |
dc.type | thesis | en_US |
dc.type.genre | thesis | en_US |
dspace.entity.type | Publication | |
relation.isOrgUnitOfPublication | 047b23ca-7bd7-4194-b084-c4181d33d95d | |
thesis.degree.discipline | Aerospace Engineering | |
thesis.degree.level | thesis | |
thesis.degree.name | Master of Science |
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