Good practise
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Domain
The domain can be as large as requested. However, placing the farfield boundaries twenty chord lengths away from the body boundaries yields domain independent results, even when strong shocks are present in the flow. Using smaller domains (down to five chord lengths) may also yield domain independent results if nonlinear effects are smaller, although it is not recommended. -
Mesh
To attain results that are grid independent, surface mesh sizes of about 1/200 of the local chord need to be considered, alongside a stretching factor for volume elements of 1.1. However, these parameters will produce large and dense meshes not suited for fast preliminary design, especially in 3D. Engineering accuracy can usually be achieved by using surface mesh sizes of 1/100 of the local chord combined with a stretching factor of 1.2. Additionally, the mesh at the trailing edge of wingtips should be coarsened to avoid the local singularity caused by the infinite speed vortex (see Known issues). -
Linear solver
For best performance, PARDISO or GMRES should be used. If memory is not a concern, PARDISO is the recommended choice. If GMRES is used to treat cases where convergence is difficult, using a fill-in factor of 3 instead of 2 for the ILU preconditioner may help.