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Job Record #17401
TitlePhD with Airbus on LES for aeroacoustics in cavities
CategoryPhD Studentship
EmployerAirbus and ISAE-Supaero
LocationFrance, Toulouse
InternationalYes, international applications are welcome
Closure DateFriday, December 31, 2021
Title: MAMBO – High-order LES of the vortex-noise coupling in deep cavities at 
high speed flows 
Certification in icing conditions of aircraft door openings requires the design 
of a small cavity along the interface between the door and the fuselage. The 
high-speed turbulent flow over this deep cavity can lead to strong noise 
generation, especially at cruise operating conditions. It results in undesired, 
and unacceptable, whistling sounds inside the cabin. From an industrial point of 
view, this issue should be taken into account at the design stage to avoid late 
and costly re-designs during flight tests. However, the underlying physics due 
to the coupling between the grazing turbulent boundary layer and the acoustics 
inside the cavity is still not fully understood. Thus, it requires advanced 
simulations tools to further understand the key phenomena generating this noise, 
in order to improve the current industrial method to predict this high-speed 
cavity noise at the design stage.
Objectives and work:
The underlying noise mechanism in the door’s cavity configuration is associated 
with an aeroacoustic coupling between the cavity and the grazing turbulent shear 
layer issued from the fuselage. A pure acoustic modelling of the modes inside 
the cavity with a standard CAA method is not able to reproduce this coupling, 
but only to find the relevant tonal frequencies that might emerge. First results 
based on a hybrid RANS/LES approach provided qualitative trends, but the high 
complexity of the interaction between the turbulent boundary layer and acoustic 
waves requires more advanced simulation tools. The goal of this PhD thesis is to 
predict accurately this noise spectrum using a state-of-the-art simulation 
method, namely High-Order Large Eddy Simulations (HO-LES) of the full 3D Navier-
Stokes problem.
To do so, an in-house HO-LES code solving the 3D compressible Navier-Stokes 
equations, named IC3 and developed at ISAE-SUPAERO, will be used. It is based on 
high-order spectral methods for the spatial discretization, which allow high 
order of convergence, up to 5th order. These methods are well adapted to 
propagate the turbulent structures inside the boundary layer, as well as the 
acoustic waves with a very low dissipation. To apply this approach and reproduce 
accurately the whistling noise, a critical ingredient is the simulation of the 
large turbulent boundary layer, representative of the one developing on the 
fuselage in cruise conditions, upstream of the cavity. To reach this goal, a 
synthetic turbulence will be implemented at the inlet of the HO-LES. This method 
needs the knowledge of the several characteristics of the boundary layer (mean 
flow, Reynolds tensor, etc.), in order to generate the synthetic turbulence by 
deconvolution. While this method has been already applied to other 
configurations, research efforts towards a robust and reliable method is still 
needed: this constitutes a second objective of this PhD. In addition, the 
effects of the spectral content of the turbulent boundary layer, as well as the 
geometry of the cavity on the noise spectrum will be investigated. Both academic 
(working with DLR, Germany) and industrial (from Airbus) geometries will be 
studied during this PhD. HO-LES simulations will be compared with the wind 
tunnel experiments carried out by DLR, as well as with the industrial tool 
available at AIRBUS. The goal is to provide a new insight on the main mechanisms 
driving this whistling sound, in order to propose relevant improvements of the 
current industrial method employed to predict this high-speed cavity noise at 
the design stage.
Required profile and skills:
The PhD candidate will have a strong background in either fluid mechanics, CFD 
and/or acoustics. Curiosity and self-working skills will be necessary to tackle 
this advanced topic. In particular, a desire to explore the capabilities of 
advanced simulation tools and physics of turbulent flows and acoustics is 
needed. Working in group is essential for this PhD, since in close collaboration 
with other PhDs working on the code IC3 and acoustics, as well as communicating 
results with Airbus. Programming skills (C++, python, etc.) will be appreciated. 
English and/or French is mandatory.
Contact Information:
Please mention the CFD Jobs Database, record #17401 when responding to this ad.
Email ApplicationYes
Record Data:
Last Modified17:36:44, Wednesday, October 20, 2021

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