System Identification of Two-Dimensional Transonic Buffet
Résumé
When modeled within the unsteady Reynolds-Averaged Navier-Stokes framework, the
shock-wave dynamics on a two-dimensional aerofoil at transonic buffet conditions is char-
acterized by time-periodic oscillations. Given the time series of the lift coefficient at different
angles of attack for the OAT15A supercritical profile, the sparse identification of nonlinear dy-
namics (SINDy) technique is used to extract a parametrized, interpretable and minimal-order
description of this dynamics. For all of the operating conditions considered, SINDy infers
that the dynamics in the lift coefficient time series can be modeled by a simple parametrized
Stuart-Landau oscillator, reducing the computation time from hundreds of core hours to sec-
onds. The identified models are then supplemented with equally parametrized measurement
equations and low-rank DMD representation of the instantaneous state vector to reconstruct
the true lift signal and enable real-time estimation of the whole flow field. Simplicity, accuracy
and interpretability make the identified model a very attractive tool towards the construction
of real-time systems to be used during the design, certification and operational phases of the
aircraft life cycle.
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