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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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.
|Document Type:||Conference or Workshop Item (Speech, Paper)|
|Title:||Time-linearized simulation of unsteady transonic flows with shock-induced separation|
|Journal or Publication Title:||Proceedings of the 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012)|
|In ISI Web of Science:||No|
|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|
|HGF - Research field:||Aeronautics, Space and Transport|
|HGF - Program:||Aeronautics|
|HGF - Program Themes:||Aircraft Research|
|DLR - Research area:||Aeronautics|
|DLR - Program:||L AR - Aircraft Research|
|DLR - Research theme (Project):||L - Simulation & Validation|
|Institutes and Institutions:||Institute of Aeroelasticity|
|Deposited By:||Daniela Erdmann|
|Deposited On:||19 Dec 2012 17:01|
|Last Modified:||19 Dec 2012 17:01|
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