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Job Record #15620
TitleLES of the flow over acoustic liners
LocationFrance, Toulouse
InternationalYes, international applications are welcome
Closure Date* None *
Porous acoustic liners have played an important role in reducing the noise 
from jet engines down to certification levels. They are also effective in 
reducing vibro-acoustic failure modes in combustion chambers of rocket 
engines which are again crucial for engine certifications and successful 
launch of the vehicle. Due to their strict noise attenuation requirements 
they are highly optimised for acoustic performance, but to the detriment of 
aerodynamic performance in the form of significant increment in skin 
friction drag. The design and optimisation tools for acoustic liners are 
quite reliable and even low order impedance models can predict the acoustic 
attenuation with high accuracy. However, the rapid drag rise in the presence 
of large amplitude acoustic sources is still not very well understood as it 
is both experimentally and numerically challenging to resolve the fine 
turbulence scales in the vicinity of the perforated surface and the cavity 
underneath. A recently published study by E. Gowree (2019) has shown that in 
the absence of external acoustic forcing, the perforated surface can have 
the opposite effect of reducing the skin friction drag. This is potentially 
due to the re-organisation of the coherent structures in the turbulent 
boundary layer by the discrete 3D circular cavities or simply the 

The aim of this internship will be to use the in-house CharLESx code to 
conduct detailed large eddy simulations. So as to further understand the 
physical mechanism responsible for the drag reduction, as well as the sudden 
drag rise at high Reynolds number, while resolving the coherent structures 
in the turbulent boundary layer. The code solves the compressible Navier-
Stokes equations on an unstructured grid using high order methods. We are 
looking for a candidate with strong knowledge in fundamental fluid mechanics 
and turbulence.  In order to run the in-house code the candidate should be 
familiar with UNIX, scripting and high performance computing.

There has already been a first campaign of simulations during an internship 
by a Masters student to validate the numerical approach and there are 
further on-going numerical activities by R. Gojon and E. Gowree. 

Contact Information:
Please mention the CFD Jobs Database, record #15620 when responding to this ad.
NameErwin Gowree
Email ApplicationYes
Record Data:
Last Modified17:48:30, Tuesday, January 29, 2019

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