Cart3D is a high-fidelity inviscid analysis package for conceptual and preliminary aerodynamic design. It was developed at NASA Ames Research Center and has been used successfully in external flow aerodynamic simulations. Cart3D is integrated into ANSYS ICEM CFD.
The component surfaces are intersected before meshing to form a single wetted surface. This detects any geometry degeneracy in the configuration and corrects it automatically thereby avoiding possible complications in the mesh generation process.
Cart3D produces topologically unstructured, adaptively refined, Cartesian meshes. The desired finest cell size can be achieved by controlling the initial mesh divisions and number of refinement levels. The adaptation region can be pre-specified in the usual manner in ICEM CFD using density control polygons.
The mesh generation operates on the order of 1M cells/minute on moderately powered workstations. It's memory usage is approximately 14 words/cell so that typically only 54MB is required to generate a mesh of 1M cells.
Currently the mesh can be saved in either a Cart3D native mesh format, or in an ICEM CFD domain file as un unstructured hex mesh. Translators can be provided within ICEM CFD to write the Cartesian mesh directly to any particular CFD solver format.
The solver is a scalable, multilevel solver for the Euler equations governing the inviscid flow of a compressible fluid. Meshes from Cart3D are treated as unstructured collections of Cartesian cells, and it takes advantage of the fact that cells are Cartesian wherever possible to reduce the operation count. Cart3D uses Full Approximation Storage (FAS) multi-grid for convergence acceleration. It uses a domain decomposition approach to parallelization. As a result, scalability on large numbers of processors is quite good. Speedups in excess of 56 on 64 processors are typical.