Computational Fluid Dynamics and Aeroacoustics

elsA Aerodynamics Simulation Software Package

Simulation of turbulent flows in external and internal aerodynamics

The elsA project (elsA standing for aerodynamics simulation software package) launched in 1997 aims to develop a unique multi-application software package for numerical simulation in aerodynamics. The elsA software package is designed both as a tool to tackle industrial problems and as a platform for CFD research. The evolving architecture of elsA at first allowed the recovery and interoperability of the capabilities of previous in-house CFD codes, and makes today easier the integration of new developments issued from CFD research.

The elsA architecture is the result of both an object-oriented software design method and an object-oriented implementation method. The elsA software package combines the C++ language, for translating object concepts, with the Fortran language for implementing time-costly scientific computation methods. The Python interpreted object-oriented language is used for the user interface. elsA calculations are run on a large variety of computer platforms including vector supercomputers, multi-processor scalar computers, Linux PC clusters.

The elsA software package is based on a finite volume method for solving the Navier-Stokes equations. The space discretization is carried out by multi-block structured meshes, with a high flexibility in the block assembly (coincident or non-coincident adjacent meshes, overlapping meshes, Chimera meshes). This flexibility makes easier to deal with complex geometries. The elsA software package allows the simulation of steady or unsteady flows, of inviscid or viscous fluids, in fixed or moving frame, in rigid or deforming meshes. When the flow regime is turbulent, turbulence is simulated, either by a time average of the Navier-Stokes equations completed by a turbulence model (RANS equations), or by a simulation of the large turbulence scales (LES method). The elsA software package also includes capabilities dealing with optimum design and with aeroelasticity.

Development of elsA is carried out, not only by the DSNA department, but also by several other departments from ONERA (DMAE, DDSS, DAAP), and by external contributors among them Cerfacs research organization is the main one. The elsA software package is used by ONERA for its own studies, by French or European industrial partners (Airbus, Eurocopter, Snecma Moteurs, Turbomeca, MBDA), by CNES and by research laboratories (Ecole Centrale de Lyon). Lastly, elsA is one of the basic software of the DLR/ONERA co-operations dealing with the development and the validation of software tools for the aerodynamics of transport aircraft and helicopter configurations, including multi-disciplinary couplings (structure mechanics, flight mechanics...).

Last Update: 13 October 2006 - © ONERA 2009 - Terms of use