Argo in a nutshell
Argo is an unstructured, massively parallel, multi-physics CFD code that includes compressible and incompressible second-order accurate finite volume/finite element schemes and implicit time-integrators based on a Newton-Krylov-Schwarz solver.
Multi-physics connections are performed with MpCCI, making possible the interconnection of Argo with acoustical propagations codes, thermal simulation packages and structural FEM software. As an example, Cenaero performed a 3-code coupling on a turbine blade cooling 3D simulation involving Argo for internal cooling of the blade.
The CFD solver Argo developed at Cenaero is a domain decomposition based parallel three-dimensional Navier-Stokes solver on unstructured tetrahedral meshes.
For RANS-type simulations, Argo features a second-order accurate solver which blends a finite volume approach for the convection fluxes based on a piecewise linear reconstruction of the variables in each control volume with a P1 finite element Galerkin approximation of the diffusion fluxes.
For LES-type applications, Argo uses a second-order non-dissipative central scheme which conserves the kinetic energy at the discrete level. For industrial high-Reynolds number flow applications, a hybrid formulation based on the DES approach derived from the one-equation Spalart-Allmaras model is implemented.
In order to achieve a discretization that is in accordance with the flow physics and the modeling strategy, the upwind scheme is used in the RANS region while the kinetic energy central scheme is active in the LES region. Pseudo time-integration is performed for steady flows with the backward Euler scheme, while the ALE version of the three-point backward difference scheme is used for unsteady flow computations on moving meshes.
The system of nonlinear equations is solved at each time-step by a powerful Newton-Krylov-Schwartz solver.
Argo can be coupled to commercial structural dynamics, structural thermal and acoustics solvers in order to perform respectively aeroelastic, aerothermal and aeroacoustic simulations. Current breakthrough developments in Argo involve higher order discretizations with a discontinuous Galerkin approach and the coupling with a Lagrangian solver.
Argo is used in various consulting projects like :
- flow analysis in a test-bench for aero-engines
- flow analysis in cryogenic valves
- flow analysis in HVAC systems
- flow analysis around airfoils
- aero-elastic analysis of a full aircraft
- aero-thermal analysis of a high pressure turbine blade
- aero-acoustic analysis of a complete landing gear,
||Argo is also used in european projects (external aerodynamics simulation of a generic aircraft, a cost-effective small aircraft and a tiltrotor aircraft within FAR-Wake, CESAR and NICETRIP; development of novel algorithms for CFD within ADIGMA).|