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a code-coupling approach to the implementation of discrete adjoint solvers based on automatic differentiation

Backhaus, Jan and Engels-Putzka, Anna and Frey, Christian (2016) a code-coupling approach to the implementation of discrete adjoint solvers based on automatic differentiation. VII European Congress on Computational Methods in Applied Sciences and Engineering, ECCOMAS Congress 2016, 5.-10. Jun. 2016, Kreta, Griechenland.

Full text not available from this repository.

Official URL: https://www.eccomas2016.org/proceedings/pdf/6428.pdf

Abstract

We propose a method for selectively applying automatic differentiation (AD) by operator overloading to develop the discrete adjoint of a turbomachinery flow solver. A fully differentiated version of the solver is generated by operator overloading using the tapeless tangent mode of ADOL-C. The differentiated solver is coupled to an undifferentiated version of the same code using message passing. The automatic differentiation is used to calculate derivatives of the flux calculation routines. The flux derivatives depending on inner cell states are sparse, and this sparsity is exploited using analytical differentiation of the spatial discretization scheme. Subsequently the sparse matrix is communicated to the undifferentiated code for solution. Turbomachinery boundary conditions may have dense Jacobians and are therefore only evaluated during the solution process. The solution of the adjoint system of equations is achieved through a preconditioned GMRES, implemented inside the undifferentiated code. A modern three dimensional contra-rotating fan stage with engineering parameterization serves as application example in order to demonstrate the technique and to perform numerical validations. The validation of gradient results is performed by comparing against results from finite differences, and the tangent forward mode.

Item URL in elib:https://elib.dlr.de/104739/
Document Type:Conference or Workshop Item (Speech)
Title:a code-coupling approach to the implementation of discrete adjoint solvers based on automatic differentiation
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Backhaus, Janjan.backhaus (at) dlr.dehttps://orcid.org/0000-0003-1951-3829
Engels-Putzka, AnnaAnna.Engels-Putzka (at) dlr.deUNSPECIFIED
Frey, ChristianChristian.Frey (at) dlr.deUNSPECIFIED
Date:June 2016
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:discrete adjoint; automatic differentiation; RANS; turbomachinery
Event Title:VII European Congress on Computational Methods in Applied Sciences and Engineering, ECCOMAS Congress 2016
Event Location:Kreta, Griechenland
Event Type:international Conference
Event Dates:5.-10. Jun. 2016
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:propulsion systems
DLR - Research area:Aeronautics
DLR - Program:L ER - Engine Research
DLR - Research theme (Project):L - Virtual Engine and Validation methods
Location: Köln-Porz
Institutes and Institutions:Institute of Propulsion Technology
Deposited By: Backhaus, Jan
Deposited On:27 Jun 2016 16:13
Last Modified:27 Jun 2016 16:13

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