Abstract
We investigate the influence of uncertain input parameters on the
aeroacoustic feedback of cavity flows. The so-called Rossiter feedback
requires a direct numerical computation of the acoustic noise, which
solves hydrodynamics and acoustics simultaneously, in order to capture
the interaction of acoustic waves and the hydrodynamics of the flow.
Due to the large bandwidth of spatial and temporal scales, a high
order numerical scheme with low dissipation and dispersion error
is necessary to preserve important small scale information. Therefore,
the open-source CFD solver FLEXI, which is based on a high-order
discontinuous Galerkin spectral element method, is used to perform
the aforementioned direct simulations of an open cavity configuration
with a laminar upstream boundary layer.
To analyse the precision of the deterministic cavity simulation with
respect to random input parameters we establish a framework for uncertainty
quantification. In particular, a non-intrusive spectral projection
method with Legendre and Hermite polynomial basis functions is employed
in order to treat uniform and normal probability distributions of
the uncertain input. The results indicate a strong, non-linear dependency
of the acoustic feedback mechanism on the investigated uncertain
input parameters. An analysis of the stochastic results offers new
insights into the noise generation process of open cavity flows and
reveals the strength of the implemented uncertainty quantification
framework.
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