Flow Simulation

The solver is a scalable, multilevel solver for Euler equations governing the inviscid flow of a compressible fluid. Meshes from ANSYS ICEM CFD Cart3D are treated as unstructured collections of Cartesian cells; the technology leverages Cartesian cells wherever possible to reduce the operation count.

ANSYS ICEM CFD 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.

Volume Mesh Generation

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.

ANSYS ICEM CFD Cart3D software 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 prespecified in the usual manner in ANSYS ICEM CFD using density control polygons.

Mesh generation operates on the order of 1M cells/minute on moderately powered workstations. 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 an ANSYS ICEM CFD Cart3D native mesh format or in an ANSYS ICEM CFD domain file as un unstructured hex mesh. Translators can be provided within ICEM CFD to write the Cartesian mesh directly to any CFD solver format.

Component-Based Approach

The geometry for ANSYS ICEM CFD Cart3D software is provided as a collection of components. Each component is a closed triangulated surface (watertight with no internal geometry) with conformal facets. The geometry model can be loaded into ANSYS ICEM CFD in the standard way, as either CAD geometry or STL data. Using the existing CAD repair tools in ANSYS ICEM CFD, the model can then be used to create closed surface components for ANSYS ICEM CFD Cart3D. Using this component-based approach, a study can be performed in which components move or change without having to regenerate a completely new surface triangulation for the modified geometry.