Required Education : PhD
Start date : 15 May 2024
Mission duration : 2 years
We have an opening for a two-years postdoc position, to focus on Large-Eddy Simulations of high turbulence levels in turbomachinery, as well as investigation of averaging methods for turbomachinery LES.
The objectives of this project are twofold:
The first objective consists in studying the effects of high turbulence levels on the boundary layer development inside a low-pressure turbine. The boundary layer transition to turbulence is a complex phenomenon, highly dependent on the upstream conditions, which is likely to modify the entire flow topology. It induces aerodynamic losses, and finally impacts the overall engine efficiency.
This project is part of a joined effort between SAFRAN HELICOPTER ENGINES, ONERA, Von Karman Institute (VKI), and CERFACS. Experimental measurements will be performed at VKI, while Reynolds Averaged Navier-Stokes (RANS) simulations will be conducted at ONERA, with a state-of-the art 4-equations model. The postdoc fellow will be in charge of conducting LES at CERFACS, which will allow to provide turbulent characteristics for RANS simulations. These simulations will also allow thorough investigations of the unsteady transitional boundary layer, and resulting losses generated.
Simulations will be conducted with AVBP, an unstructured and massively parallel LES solver, which has demonstrated its ability to simulate low-pressure turbines and challenging configurations. A significant attention will be paid to the numerical methods and the mesh quality.
The second objective of this work is to investigate averaging methods of LES quantities for turbomachinery flows. Dedicated averaging methods have been developed in literature to allow comparisons between experimental measurements, RANS and LES results. These averaging techniques intend to transform 2D measurement planes into 1D or 0D values, to connect the 3D unsteady flow to the theoretical 0D thermodynamical cycle. These operators are constructed so that they ensure conservation of mass, momentum, enthalpy, as well as equation of state. The second objective of this work is to assess these spatial averaging operators in an unsteady context. Numerous academical flows will be investigated (pulsated pipes, wakes, unsteady turbomachinery, …). A particular attention will be paid to the spectral and modal content of the investigated flows. Eventual reformulation of averaging operators will be proposed.
The candidate should hold a PhD degree in mechanical engineering, aeronautics, fluid mechanics or any related field. He/she would have experience/knowledge in turbomachinery flow physics, Large-Eddy Simulations, High-Performance Computing, turbulence, thermodynamics. Experience with programming (Python, Fortran) and numerical methods is a major plus.
The candidate is expected to be self-motivated, willing to learn the considered LES solver, to conduct research and communicate results in conferences and journals.
In practise/ Contact:
The position will be held at CERFACS (Toulouse, France). The candidate will work within a dynamic team of PhDs and postdocs, with high academic potential and strong relations with industrial partners.
Net salary: around 2400 euros/month.
Expected beginning: May / June 2024
Send CV and cover letter + name of 2 references contacts.
Nicolas Odier / firstname.lastname@example.org
Florent Duchaine / email@example.com
Laurent Gicquel / firstname.lastname@example.org