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Time-linearized simulation of unsteady transonic flows with shock-induced separation

Thormann, Reik and Nitzsche, Jens and Widhalm, Markus (2012) Time-linearized simulation of unsteady transonic flows with shock-induced separation. In: Proceedings of the 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012). TU Wien. ECCOMAS 2012 - 6th European Congress on Computational Methods in Applied Siences and Engineering, 10.-14. Sept. 2012, Wien, Österreich. ISBN 978-3-9502481-9-7

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Abstract

During flutter analysis of a new aircraft a huge number of unsteady aerodynamic simulations is necessary in the parameter space consisting of Mach number, aeroelastic trim state, structural mode shape and frequency. For subsonic flow conditions fast potential methods like the Doublet Lattice Method can be applied. In the transonic regime unsteady flow perturbations depend on the mean flow state and CFD methods have to be employed. However, solving the nonlinear unsteady RANS equations for thousands of parameter combinations is not applicable. Hence, faster CFD methods are needed to reduce the computational costs. Assuming small time-harmonic perturbations, the RANS equations can be linearized around the steady mean solution. The latter are preferably solved in the frequency domain. This results in a large, sparse linear system for the perturbation of the fluid unknowns. In this paper an efficient time-linearized solver (LFD-TAU) is presented with special focus on 2-d external flows with strong shock-induced separation. The results are compared to small-amplitude pulse response and single-frequency RANS simulations, demonstrating good agreement over a wide frequency range. Even under pre-buffet flow conditions, showing aerodynamic resonance peaks, the resonance frequency is captured well, while the amplitudes are overestimated.

Item URL in elib:https://elib.dlr.de/79167/
Document Type:Conference or Workshop Item (Speech, Paper)
Title:Time-linearized simulation of unsteady transonic flows with shock-induced separation
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Thormann, Reikreik.thormann (at) dlr.deUNSPECIFIED
Nitzsche, Jensjens.nitzsche (at) dlr.deUNSPECIFIED
Widhalm, Markusmarkus.widhalm (at) dlr.deUNSPECIFIED
Date:2012
Journal or Publication Title:Proceedings of the 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012)
Refereed publication:No
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Editors:
EditorsEmail
Eberhardsteiner, JosefTU Wien
Böhm, Helmut J.TU Wien
Rammerstorfer, Franz G.TU Wien
Publisher:TU Wien
ISBN:978-3-9502481-9-7
Status:Published
Keywords:unsteady aerodynamics, linearization, transonic, separation
Event Title:ECCOMAS 2012 - 6th European Congress on Computational Methods in Applied Siences and Engineering
Event Location:Wien, Österreich
Event Type:international Conference
Event Dates:10.-14. Sept. 2012
Organizer:TU Wien
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research (old)
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Simulation & Validation (old)
Location: Göttingen
Institutes and Institutions:Institute of Aeroelasticity
Deposited By: Erdmann, Daniela
Deposited On:19 Dec 2012 17:01
Last Modified:19 Dec 2012 17:01

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