Sorry, you need to enable JavaScript to visit this website.
An official website of the European UnionAn official EU website
English (en)
TRIMIS

Non-deterministic simulation for CFD-Based Design methodologies

NODESIM-CFD

Non-deterministic simulation for CFD-Based Design methodologies

Call for proposal: 
FP6-2005-AERO-1
Link to CORDIS:
Background & policy context: 

Analysis and design methods in aeronautical industry, particularly the aerodynamic simulation tools based on Computational Fluid Dynamics (CFD) and their multidisciplinary extensions (such as fluid-structure; fluid-thermal; aero-acoustics applications), are based on simulations with a unique set of input data and model variables. However, realistic operating conditions are a superposition of numerous uncertainties under which the industrial products operate (uncertainties on boundary and initial conditions, on geometries resulting from manufacturing tolerances, numerical error sources and uncertain physical model parameters. The presence of these uncertainties is the major source of risk in the design decision process and increases therefore the level of risks of failure of a given component.

Objectives: 

The NODESIM-CFD project addressed the EU objectives of reduction of aircraft development costs and increase of safety, through the introduction of a new paradigm for computational fluid dynamics (CFD)-based virtual prototyping, aimed at the incorporation of operational and other uncertainties in the simulation process. The project pursued the following scientific and technological objectives:

  1. identification and quantification of the uncertainty parameters associated to a wide variety of aeronautical applications; the domains of application cover: engine aerodynamics, wing aerodynamics, conjugate heat transfer and fluid-structure interactions;
  2. development of several non-deterministic methodologies focusing on the most promising methods, such as perturbation techniques and adjoint-based methods, efficient Monte Carlo (MC) methods and polynomial chaos methods;
  3. applications to subsystems and systems: the general methodologies and software tools developed under the previous actions will be applied, tested and validated for the various applications for which the uncertainty variables have been identified and analysed;
  4. introduction of non-deterministic simulations into the design and decision process, focusing on the development of aerodynamic optimisation algorithms that provide designs, which are robust with respect to uncertainties in geometry, operating conditions, and code simulation uncertainties, and to control and reduce risks by providing designs with aerodynamic performances insensitive to intrinsically uncertain quantities;
  5. stimulate the scientific cooperation and transfer of knowledge within the NODESIM-CFD consortium, through a specific task of support from the developers to the implementation of the developed new methodologies in the in-house codes of the industrial partners.
Methodology: 

The NODESIM-CFD project was composed of the following action lines:

  • the identification and probabilistic quantification of the most significant uncertainty sources, related to CFD and multidisciplinary based simulations, of aeronautical components (wings, aircraft and engines);
  • the development and incorporation of efficient non-deterministic methodologies into the CFD simulation systems to produce reliability bounds of the predictions in a rational way;
  • application and evaluation of the developed methodologies to the non-deterministic analysis of aeronautical components by the industrial manufacturers;
  • the development and application of robust CFD-based design methodologies incorporating the non-deterministic based simulations, enabling rational estimates of probabilities of failure.
Institution Type:
Institution Name: 
European Commission
Type of funding:
Key Results: 

The first objective has been accomplished by an intensive and thorough analysis of the potential uncertainties to be accounted for. Three classes of uncertainties were identified: operational, geometrical and numerical uncertainties. The identified uncertainties are statistically described through a probability distribution functions (PDF). In order to prescribe the input parameters of a selected PDF based on expert opinion or to identify the type of PDF from experimental data two software tools have been developed: a beta PDF defining tool and a distribution fitting tool.

The second objective, namely the development of the non-deterministic methodologies for uncertainty propagation represented the core of the NODESIM-CFD project. Three categories of non-deterministic methodologies were developed and applied:

  • perturbation techniques with adjoint methods;
  • MC methods with surrogate methods;
  • polynomial chaos methods (PCMs).

The third listed objective aimed at validating the non-deterministic methodologies on representative test cases and for various uncertainties sources. Therefore, a database of test cases has been built up with different levels of complexity. Academic test cases and industrial ones coexisted and have been classified following the range of applications: external flows around wings, propulsion flows and multi-physics. As applications to external flows around the wings, the transonic flows around the RAE 2822 airfoil and ONERA M6 wing have been selected as compulsory tests.

With respect to applications to propulsion flows the transonic flow in NASA Rotor 37 configuration has been selected as compulsory test case. As applications to multi-physics the flutter of AGARD 445.6 wing, an aero-elastic of wing model and a planar combustor test rig have been considered.

The last two objectives have foreseen actions for the transfer of knowledge among the developers' teams and the end-user partners. This was a two way process: a direct action was dedicated to the actual transfer of the non-deterministic software modules, coupling with end-users' in-house codes and training. An important feed-back arrived from the end-users towards the developers on the appropriateness of a specific uncertainty propagation method with respect with a range of applications and suggestions of improvement.

Technical Implications

For the first category of techniques, actions were directed towards the automatic differentiation for the management of uncertainties, studies on the influence of the computational mesh on the drag and lift output functionals and an adjoint-based error estimator have been developed. Inria succeeded in identifying and implementing strategies for computing second derivatives of CFD codes, while the German Aerospace Centre (DLR) developed an error-based adaptation technique.

The second category of developed non-deterministic methodologies aimed at circumventing the high computational cost and consequently the MC analysis systems were combined with surrogate models based on various response surface methods or design of experiments.

CIMNE has achieved the adaptation and integration in its Monte-Carlo analysis system stochastic analysis computation (STAC) of new capabilities related to the needs of multidisciplinary codes. Among these capabilities, one can underline the generation of random variables from given marginal distribution as well as a joint distribution of all the variables and STAC's usage for robust design.

ONERA focused on the following surrogate models in combination with their developed MC method: eight order polynomial approximation, radial basis function neuronal network and simple Kriging. SIGMA focused in turn to surrogate model construction tools based on polynomial regression, simplified 'weighted' approximation and radial basis function neuronal networks. UNITS developed DACE technologies with the classical and adaptive versions particularly.

The third category of non-deterministic methodologies accounts for two main types of PCMs: intrusive and non-intrusive. For both types of PCM, the principal interest was concentrated on the assessment of the effects due to the nonlinear character of the flow governing system and to improve the computational efficiency. VUB developed an intrusive PCM, tested by NUMECA, and non-intrusive probabilistic collocation methods were developed by QQ and WSA. In addition TUD developed also the probabilistic radial basis function approach.

Lead Organisation: 

Numerical Mechanics Application International

Address: 
5 Avenue Franklin Roosevelt
1050 BRUSSELS
Belgium
EU Contribution: 
€0
Partner Organisations: 

Deutsches Zentrum Fr Luft Und Raumfahrt E.v

Address: 
Linder Hoehe
51147 KOELN
Germany
EU Contribution: 
€0

Alenia Aermacchi Spa

Address: 
Viale Dell'aeronautica Snc
80038 Pomigliano D'arco (Na)
Italy
EU Contribution: 
€0

Dassault Aviation

Address: 
9, Rond-Point des Champs-Elysées - Marcel Dassault
75008 PARIS
France
EU Contribution: 
€0

Qinetiq Limited

Address: 
85 Buckingham Gate, 2nd Floor
LONDON
United Kingdom
EU Contribution: 
€0

Centre Internacional De Metodes Numerics En Enginyeria

Address: 
C Gran Capitan, Edifici C1, Campus Nord Upc Sn
8034 Barcelona
Spain
EU Contribution: 
€0

Engin Soft Tecnologie Per L'ottimizzazione Srl

Address: 
Via Malfatti 21
TRENTO
Italy
EU Contribution: 
€0

Institut National De Recherche En Informatique Et Automatique

Address: 
Domaine de Voluceau- Rocquencourt
B.P. 105 LE CHESNAY
France
EU Contribution: 
€0

Man B&w Diesel Aktiengesellschaft

Address: 
Stadtbachstraase 1
86153 AUGSBURG
Germany
EU Contribution: 
€0

Office National D' Etudes Et De Recherches Aérospatiales

Address: 
29, avenue de la Division Leclerc
BP72 CHÂTILLON CEDEX
France
EU Contribution: 
€0

Npo Saturn Joint Stock Company

Address: 
163, Lenina Prospect
RYBINSK, YAROSLAVL REGION
Russia
EU Contribution: 
€0

Sigma Technology

Address: 
20, Elektrozavodskaia st.
MOSCOW
Russia
EU Contribution: 
€0

University Of Trieste

Address: 
via Valerio 10
TRIESTE
Italy
EU Contribution: 
€0

Delft University Of Technology

Address: 
Mekelweg 5
2628 CD Delft
Netherlands
EU Contribution: 
€0

Vrije Universiteit Brussel

Address: 
Pleinlaan
1050 Brussel
Belgium
EU Contribution: 
€0

Atkins Advantage Technical Consulting Limited

Address: 
WOODCOTE GROVE, ASHLEY ROAD
EPSOM, SURREY
KT18 5BW
United Kingdom
EU Contribution: 
€0

Airbus Operations Limited

Address: 
New Filton House, Filton
BRISTOL
BS99 7AR
United Kingdom
EU Contribution: 
€0