Transonic Extension
The FlightStream transonic solver is based on a field-panel approach to solving the full-potential equation. Using Green’s theorem, the velocity potential of a compressible, inviscid flow may be obtained as the sum of a surface distribution of sources and doublets (on the surface of the body being analyzed) and a volume distribution of sources. These volume sources represent compressibility effects and their strengths are calculated from the full-potential equation.
Within the field panel solver, an incompressible solution is first obtained from the classic FlightStream solver
on the surface of the configuration. This initial solution is then used to estimate the volumetric source strengths. Their influence on the body may then be calculated and incorporated into the incompressible surface solution as modified velocity flux boundary conditions. The surface is then resolved with these updated boundary conditions, and the process iterates until the surface and volume solutions have converged.
The FlightStream field-panel solver includes numerous modernizations compared to legacy field-panel codes, such as the use of far-field singularity agglomeration for fast influence calculations. In addition, the volume solution is calculated on an unstructured, Cartesian octree grid, which is generated automatically by FlightStream without any user input. Surface intersections with the volume grid are also handled automatically, removing the major pain points present with standard volumetric CFD.