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 # Ansys Common Fluids Data Models 

 Last update: 16.07.2025 

# <a class="anchor" id="ProjectDM"></a>Project Data Model

The Project data model allows relationships between data models to be expressed. It may also be used to express sequences of run outputs which might typically be seen for transient runs and parametric stufies.

Project models may refer to multiple [CFF Restart Data Model](_data_models_overview.xhtml#RestartDM) and [CFF Post Data Model](_data_models_overview.xhtml#PostDM) models.

See [Project API](_project_a_p_i.xhtml) for further details.

# <a class="anchor" id="RestartDM"></a>CFF Restart Data Model

The Common Fluids Format API depends on data being stored within a number of different files that contain data models that represent the [Mesh](_mesh_d_m.xhtml), [Topology](_topology_d_m.xhtml), [Physics](_settings_d_m.xhtml#PhysicsDM), and [Solution](_solution_d_m.xhtml) data.

## <a class="anchor" id="RestartMesh"></a>Mesh Requirements

[Mesh](_mesh_d_m.xhtml) should only be defined using the [Cell/Node Definition](_mesh_d_m.xhtml#CellNodeDefinition) (where cells are defined by a sequence of nodes) or the [Face/Node Definition](_mesh_d_m.xhtml#FaceNodeDefinition) (where faces are defined by nodes and the faces have cell parents).

NoteIf you model contains Polyhedral cells, you should use the [Poly/Face Definition](_mesh_d_m.xhtml#PolyFaceDefinition). Instead the [Face/Node Definition](_mesh_d_m.xhtml#FaceNodeDefinition) should always be used.## <a class="anchor" id="RestartTopology"></a>Topology Requirements

It is recommended that a Topology Model is supplied. For Mesh only files this data can be ommitted.

The [Topology](_topology_d_m.xhtml) provides a valuable connection between the data within the [Physics Model](_settings_d_m.xhtml#PhysicsDM) and the [Mesh Model](_mesh_d_m.xhtml).

In the case of Ansys Fluent, this data is not yet written but can be built using the `ansys::LocationModelBuilder` utility.

## <a class="anchor" id="RestartPhysics"></a>Physics Requirements

Physics should be provided when appropriate. For Mesh only files this data can be ommitted.

## <a class="anchor" id="RestartProject"></a>Project Data

The associations between models in a fluid simulation may be represented in a [Project](_data_models_overview.xhtml#ProjectDM).

# <a class="anchor" id="PostDM"></a>CFF Post Data Model

The CFF Post Data Model provides a very simplified model when compared to the [CFF Restart Data Model](_data_models_overview.xhtml#RestartDM). The [Mesh](_mesh_d_m.xhtml) will only contain simple [Zones](_mesh_d_m.xhtml#MeshZone) that represent regions of mesh intended for fast Post Processing purposes. [Topology](_topology_d_m.xhtml) and [Physics](_settings_d_m.xhtml#PhysicsDM) should nto be written. [Solution](_solution_d_m.xhtml) data should be provided when required for Post Processing.

## <a class="anchor" id="PostMesh"></a>Mesh Requirements

[Mesh](_mesh_d_m.xhtml) data must always be provided in a [Cell/Node Definition](_mesh_d_m.xhtml#CellNodeDefinition) for all Cells other than polyhedral cells. Polyhedral cells or zones that contain polyhedral cells should always be specified using a [Poly/Face Definition](_mesh_d_m.xhtml#PolyFaceDefinition).

NoteEach [Face Zone](_mesh_d_m.xhtml#FaceZones) and each [Cell Zone](_mesh_d_m.xhtml#CellZones) will refer to a [Node Zone](_mesh_d_m.xhtml#NodeZones) that is unique i.e. all [Face Zones](_mesh_d_m.xhtml#FaceZones) and [Cell Zones](_mesh_d_m.xhtml#CellZones) are always disconnected.## <a class="anchor" id="PostTopology"></a>Topology Requirements

[Topology](_topology_d_m.xhtml) should not be provided by a [CFF Post Data Model](_data_models_overview.xhtml#PostDM).

## <a class="anchor" id="PostPhysics"></a>Physics Requirements

[Physics](_settings_d_m.xhtml#PhysicsDM) should not be provided by a [CFF Post Data Model](_data_models_overview.xhtml#PostDM).

## <a class="anchor" id="PostSolution"></a>Solution Model Requirememts

[Solution](_solution_d_m.xhtml) data is always stored on node locations. The values should require no further manipulation in order for you to accruately process the data within your application or a post-processor (e.g. Ansys EnSight or Ansys CFD-Post).

NoteEach face and cell zone may contain solution values that correspond to the distinct nodes against which the face and cell zones are defined. Although this implies data may be duplicated, it means that data can be accessed more quickly and with less memory overhead is required for data access on a subset of the [Zones](_mesh_d_m.xhtml#MeshZone).## <a class="anchor" id="PostProject"></a>Project Data

The associations between models in a fluid simulation may be represented in a [Project](_data_models_overview.xhtml#ProjectDM).

# <a class="anchor" id="DataModelsIndex"></a>Data Models

- [Mesh Data Model](_mesh_d_m.xhtml)
- [Topology Data Model](_topology_d_m.xhtml)
- [Setting Data Model](_settings_d_m.xhtml)
- [Solution Data Model](_solution_d_m.xhtml)