Efficient unsteady aerodynamic loads prediction based on nonlinear system identification and proper orthogonal decomposition

Maximilian Winter, Christian Breitsamter

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


In the present work, an efficient surrogate-based framework is developed for the prediction of motion-induced surface pressure fluctuations and integral force and moment coefficients. The model construction is realized by performing forced-motion computational fluid dynamics (CFD) simulations, while the result is processed via the proper orthogonal decomposition (POD) to obtain the predominant flow modes. Subsequently, a nonlinear system identification is carried out with respect to the applied excitation and the resulting POD coefficients. For the input/output model identification task, a recurrent local linear neuro-fuzzy approach is employed in order to capture the linear and nonlinear characteristics of the dynamic system. Once the reduced-order model (ROM) is trained, it can substitute the flow solver within unsteady aerodynamic or aeroelastic simulation frameworks for a given configuration at fixed freestream conditions. For demonstration purposes, the ROM approach is applied to the LANN wing in high subsonic and transonic flow. Due to the characteristic lambda-shock system, the unsteady aerodynamic surface pressure distribution is dominated by nonlinear effects. Numerical investigations show a good correlation between the results obtained by the ROM methodology in comparison to the full-order CFD solution. In addition, the surrogate approach yields a significant speed-up regarding unsteady aerodynamic calculations, which is beneficial for multidisciplinary computations.

Original languageEnglish
Pages (from-to)1-21
Number of pages21
JournalJournal of Fluids and Structures
StatePublished - 1 Nov 2016


  • Neuro-fuzzy models
  • Nonlinear system identification
  • Proper orthogonal decomposition
  • Reduced-order modeling
  • Transonic flow
  • Unsteady aerodynamics


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