Traditional pre-processors define a simulation model for a specific geometry or a mesh. When the geometry changes, the model set-up has to be adapted or, depending on the nature of the changes, completely redone. Abstract models define a simulation set-up in a geometry and mesh independent way, which makes Abstract Models re-usable for any product shape whether it differs just minimally or radically.
In an Abstract Model, material information, volume and boundary conditions are applied to abstract (not explicit shapes) geometry classes instead of geometrical entities or mesh regions.
The real simulation model is created when an Abstract Model is combined with a CFD CAD model. In simulation model, these abstract classes get associated with the real geometry entities by matching strings attached on real geometry entities with name of abstract geometry classes. This real simulation model is used for automatic mesh generation, application of all necessary material information, boundary- and volume-conditions as well creation of the CFD solver input deck.
The creation and testing of Abstract Models requires CFD expertise and is done by analysts; the use of Abstract Models needs no CFD knowledge. Selecting a best practice Abstract Model and relevant CAD geometry to work with is all that a designer has to do to get a reliable CFD simulation started.