Speaker
Mr
Zamashobane Zama
(University of Cape Town)
Description
This study considers a numerical approach to identifying noise mechanisms in tandem
cylinders to understand aircraft landing gear as a primary contributor to airframe noise
during approach and landing. Fluctuations in the flow properties induced by turbulence
are computed as well as the corresponding propagations. A hybrid IDDES turbulence
model is employed, to compute the boundary layer and fluctuations in the flow properties. Larsson et al. modified Curle’s analogy leading to the derivation of a version of
Curle’s analogy that makes use of strictly time derivatives which has been proven to be
less sensitive to numerical errors. Brentner and Farassat derived a formulation of the
Ffowcs-Williams and Hawkings analogy for a permeable surface enclosing the acoustic
sources which accounts for the quadrupole acoustic sources in the flow without the costly
calculation of a volume integral. This study will consider the impact of neglecting the
volume sources through a comparison of the two modified versions of Curle’s and FWH
analogies with the results of other CFD practitioners as well as experimental data.
HPC content
For this study, the CHPC large cluster was used. This is because the resolution requirements were high due to the need to be able to resolve tiny noise producing turbulent structures as well as achieving a W
wall-normal distance (y+) that is approximately equal to one.
Primary author
Mr
Zamashobane Zama
(University of Cape Town)
