Novel hybrid LES-RANS schemes for simulating physically and geometrically complex turbulent flows

Lead Research Organisation: University of Manchester
Department Name: Mechanical Aerospace and Civil Eng

Abstract

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.
 
Description In turbulent Computational Fluid Dynamics (CFD) Direct Numerical Simulation (DNS) is a deterministic approach resolving the entire range of turbulent flow structures down the tiniest ones that molecular viscosity will allow. This requires 100 million-cells meshes and precise numerical methods, but no modelling assumption is made. DNS, a "flawless numerical experiment", is however limited to plain and small-extent geometries (only 10 to 100 times the largest eddy) with simplistic inlet conditions (often periodic: inflow = outflow).

Inversely, the industrial CFD workhorse is Reynolds Averaged Navier Stokes (RANS) tentatively predicting only statistical values - mean velocity, temperatures and their variance - which is fast and, with fully unstructured meshes, applicable to very complex geometries.

To study less trivial and larger geometries UoM and EDF have jointly developed over 10 years coupling of RANS and Large Eddy Simulation (LES is like DNS but with still some statistical model for the smaller eddies). The method is based on correcting the stresses in the LES using those given by the RANS on coarse mesh regions, and vice-versa, has successfully predicted e.g. thermal mixing in a T pipe junction, separations in a diffuser or on a blade at incidence
Exploitation Route This has contributed to a series of specialised conferences,
"Symposium on Hybrid RANS-LES Methods "
first in the Eu and now world-wide, for applications in any fluid flow simulation related topical area

http://www.hrlm-symposium.org (US)
http://www.hrlm-4th.org (China)
Sectors Aerospace, Defence and Marine,Agriculture, Food and Drink,Chemicals,Digital/Communication/Information Technologies (including Software),Energy,Environment,Manufacturing, including Industrial Biotechology,Transport
 
Description Combining both, statistical (RANS) & deterministic (LES) representations of turbulence, enables localised refined studies embedded in global industrial simulations. Developed via EU projects with major aerospace industries as EADS, Dassault ... (DESIDER, ATAAC, continuing with Go-Hybrid). Extended to heat transfer, it is used with EDF for thermal stresses impact on power plant lifetime. CD-Adapco, 2nd worldwide CFD software vendor, is implementing it for local-global effect of e.g. car mirrors acoustics and drag. Following, Academics now recognised the need to use this "two fields" approach since combining RANS and LES in a single field fails for physical reasons.
First Year Of Impact 2014
Sector Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Energy,Transport
Impact Types Economic,Policy & public services
 
Description EDF Energy, EDF R and D UK centre 
Organisation EDF Energy
Country United Kingdom 
Sector Private 
PI Contribution Developed advanced turbulence models in company's flow simulation software
Collaborator Contribution Benchmarking and application of turbulence models
Impact Part of wider U. Manchester / EDF Energy UK and EDF R&D France collaboration on engineering simulation software for both fluids and solids.
Start Year 2008