Information about the division
The Division of fluid dynamics carries out research in a wide range of applications such as aerospace (which is largest), automotive, windpower, hydropower, medicine, process industry, vehicle aerodynamics, shipping, and bio-mechanics. Almost every single research project is carried out in cooperation with a company. We do both numerical simulations and experiments. We develop our own in-house CFD codes for both incompressible and compressible flow, aero and vibro-acoustics as well as system analysis of gas turbines and we are very active in the OpenFOAM community. We have a fully equipped laboratory with three large windtunnels, full set of PIV and IR imaging equipment. We do research on turbulent incompressible and compressible single and multiphase flows through numerical and experimental research and develop new and improved turbulence and multiphase models and experimental techniques for both fundamental and real-world flows. We frequently build dedicated experimental facilities in collaboration with industry in order to better understand fluid flow details. The division also works on flow induced noise applied to aerospace and automotive. In the turbomachine group, the research is focused on turbomachinery and propulsion engineering, developing new fluid machinery and gas turbine system analysis. The research also includes air traffic management.

Background to the project: Design of an electric aircraft
When designing aircrafts weight is everything. Existing batteries cannot store enough energy per kilogram. Hence, long-distance electrically propelled aircraft must – at least today – be a hybrid meaning that the aircraft would need to carry both an electric engine and a convectional turbo-prop.
For small, short-haul planes, however, the batteries will be enough. Fitting existing aircrafts with electric engines is of course the easist way to get an electricity-driven aircraft. But it may not be the best. Many airline firms that plan to go electric start from scratch, using airframes made from carbon plastics and sometime also specially designed engines. One is the Swedish airline firm Heart. see https://heartaerospace.com

The project
In the proposed project we will use the LUMA code (see below) to study the aero-dynamics of Heart’s new electric aircraft. The LUMA code will be run on GPU:s (Graphic Process Unit) using the Lattice-Boltzmann Method and it is extremely fast. GPU clusters at C3SE, Chalmers, and at NSC, Linköping, will be used. The meshing with LUMA is very fast since it is based on the Lattice-Boltzmann Method. The body of the aircraft is simply defined by a color function (it is zero when a cell is located in a solid region and one for a fluid). This makes LUMA a suitable tool for performing parametric studies. In the project we will focus on take-off and landing conditions. There are a number of open questions regarding electric aircrafts.
o Electric motors are much lighter than conventional turbo-prop engines. This
means that for an electric aircraft there is much more options where to place
the motor (e.g. further from the fuselage)
o Depending on where the electric motor is placed the interaction of propellers
and the fuselage will
– affect radiated aeroacoustic noise
– increase or decrease the aerodynamic efficiency
o Conventional aircraft wings are designed to withstand aerodynamic and mass
loads since they carry distributed jet fuel.
– What could be the effects on wings when they have to carry batteries?
– The batteries will form point sources which is very different to the distributed
jet fuel. Will this make flutter (wing oscillations) more likely?
o The speed of an electric aircraft is lower than a conventional one. This increases
the scope of designing wings with laminar flow over a large part of
the wing.

Methods, The LUMA code
The LUMA code is an open-source code based based on the Lattice-Boltzmann Method. It was developed at the University of Manchester. The object was to build a collaborative research environment in which researchers of all abilities can study fluid–structure interaction (FSI) problems in engineering applications from aero-dynamics to medicine. It is built on the principles of accessibility, simplicity and flexibility. The LUMA software at the core of the project is a capable FSI solver with turbulence modelling and many-core scalability as well as a wealth of input/output and pre- and post-processing facilities. The software has been validated and several major releases benchmarked on supercomputing facilities internationally. LUMA is written in C/C++ and designed for an x64 machine running Linux, MacOS or Windows. The software may be compiled to run in serial or parallel depending on requirements and target platform capabilities. A fork of the LUMA code has been developed and optimised for use on manycore Graphics Processing Units (GPU) hardware, which enables significantly accelerated calculations. In this content the capability for interactive post processing is implemented as a means of fast exploration of the parameter space. For more info, see:
A.R.G. Harwood, J. O'Connor, J. Sanchez Munoz, M.-C. Santasmasas, A. J.Revell, "LUMA: A many-core, Fluid–Structure Interaction solver based on the Lattice-Boltzmann Method", SoftwareX, Volume 7, 2018, Pages 88-94

Participants
The following senior reserchers will be involved in the project:
- Prof. Lars Davidson, Department of Mechanics and Maritime Sciences (project leader), http://www.tfd.chalmers.se/~lada/
- Dr. Hua-Dong Yao, Department of Mechanics and Maritime Sciences, http://www.chalmers.se/sv/personal/Sidor/huadong-yao.aspx
- Alistair Revell, Manchester University, who is responsible for the development and maintenance of LUMA.
https://www.research.manchester.ac.uk/portal/alistair.revell.html
- Dr. Anders Forslund, CEO of Heart, will supply CAD files of their electric 19-seater aircraft.
The Heart company is the result of the Vinnova project ”Elise - Electric air transport in Sweden”, a collaboration between Chalmers, KTH, Link ̈oping University, Luleå University of Technology, Uppsala University and RISE, as well as the companies Heart Aerospace, Abtery, Elite Composite and Icarus Simulation. SAAB and GKN Aerospace as well as Swedavia, LFV and the Swedish Aviation industry sit on the project’s advisory board. Anders Forslund was the initiator of the Elise project a year ago, when he worked as a researcher at Chalmers. The goal of Elise is to create a Swedish electric aviation industry, supported by research, and to develop electric aircrafts adapted to Swedish needs.

Major responsibilities
Your primary responsibility will be to pursue research and development related to flow using the Lattic-Bolzmann method. You are expected to develop your own scientific ideas and concepts, and to communicate the results of your research verbally and in writing. You will be guided by senior researchers at the involved departments. If the applicant is interested, the position also includes opportunities for supervising MSc anf BSc students. The position is meritorious for future research duties within academia as well as industry/the public sector.

Research to be carried out by the succesful applicant:
• Carry out DES/LES simulations on GPU nodes using the NUMA code
• Analyze and try to understand the physics
• In the proposed project, treatment of boundary layers in the LUMA code will be improved. Different methods will be considered.
1. incorporation of wall functions.
2. improving efficiency of embedded refinement approaches.
3. implementing a dual mesh dual solver approach near the walls. RANS would be used near the walls.
• Write scientific journal paper(s)

Position summary
The position is a full-time employment with a competitive salary and with social benefits. This position is limited to two years with current funding. If the applicant is very succesful and if new external funding is available, the position may be extended another one or two years. Start in Spring 2020 (not later than July 1). 

Qualifications
To qualify for the position of postdoc, you must have a doctoral degree in a relevant field; mechanical engng, Physics, Math. Engng, Aeronautics or any corresponding PhD. The degree should generally not be older than three years. You are expected to be somewhat accustomed to teaching, and to demonstrate good potential within research and education.

The position requires sound verbal and written communication skills in English. Chalmers offers Swedish courses.

Chalmers continuously strives to be an attractive employer. Equality and diversity are substantial foundations in all activities at Chalmers.

Our offer to you
Chalmers offers a cultivating and inspiring working environment in the dynamic city of Gothenburg
Read more about working at Chalmers and our benefits for employees.

Application procedure
The application should be marked with Ref 20190594 and written in English. The application should be sent electronically and be attached as pdf-files, as below:

CV: (Please name the document as: CV, Surname, Ref. number) including:
• CV, include complete list of publications
• Previous teaching and pedagogical experiences
• Two references that we can contact.

Personal letter: (Please name the document as: Personal letter, Family name, Ref. number)
1-3 pages where you:
• Introduce yourself
• Describe your previous research fields and main research results
• Describe your future goals and future research focus

Other documents:
• Attested copies of completed education, grades and other certificates.

Please use the button at the foot of the page to reach the application form. The files may be compressed (zipped).

Application deadline: 31 January 2019

For questions, please contact:
Lars Davidson, Strömningslära lada@chalmers.se

 



*** Chalmers declines to consider all offers of further announcement publishing or other types of support for the recruiting process in connection with this position. *** 
   



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