Output Formats

Output Formats#

Flow360 supports multiple file formats for simulation results. This page explains the available formats and their usage.

Supported Formats#

Flow360 supports the following output formats:

  • ParaView - Open-source, multi-platform visualization application

  • Tecplot - Commercial visualization software with advanced CFD features

  • VTK-HDF - HDF5-based VTK container

  • EnSight Gold - Portable case-based format

  • CSV - Simple tabular data format for Excel or other analysis tools

Outputs are written using the Output Format control, which is multi-select so a single output can be saved in several formats at once. Volume, surface, slice, and isosurface outputs support the extended VTK-HDF and EnSight formats in addition to ParaView and Tecplot:

  • paraview - ParaView format (.vtu / .vtp)

  • tecplot - Tecplot format (.szplt)

  • vtkhdf - VTK-HDF format (.vtkhdf)

  • ensight - EnSight Gold format (.case + .geo)

Note: The Output Format control is multi-select: to write both ParaView and Tecplot, select paraview and tecplot together (this replaces the earlier single both option). Surface slice output supports paraview only.

Format Details#

ParaView Format#

ParaView is an open-source, multi-platform data analysis and visualization application.

  • Volume Output: .vtu files (unstructured grid)

  • Surface Output: .vtp files (polygonal data)

  • Slice Output: .vtp files (polygonal data)

  • Isosurface Output: .vtp files (polygonal data)

Tecplot Format#

Tecplot format is a commercial visualization format with strong CFD-specific features.

  • Volume Output: .szplt files

  • Surface Output: .szplt files

  • Slice Output: .szplt files

  • Isosurface Output: .szplt files

VTK-HDF Format#

HDF5-based VTK format, readable by recent versions of ParaView.

  • Volume Output: .vtkhdf files

  • Surface Output: .vtkhdf files

  • Slice Output: .vtkhdf files

  • Isosurface Output: .vtkhdf files

EnSight Format#

EnSight Gold case-based format, read by ParaView and EnSight.

  • Volume Output: .case + .geo files

  • Surface Output: .case + .geo files

  • Slice Output: .case + .geo files

  • Isosurface Output: .case + .geo files

CSV Format#

CSV (Comma-Separated Values) is a simple tabular format that can be opened in Excel or any spreadsheet application.

  • Probe Output: .csv files

  • Surface Probe Output: .csv files

  • Surface Integral Output: .csv files

  • Aeroacoustic Output: .csv files

Multi-File Management#

Single Files vs. Multiple Files#

For surface outputs, Flow360 provides options to manage multiple geometry elements:

  • Write to Single File: When enabled, all surfaces are written to a single file

  • Write to Multiple Files: When disabled, each surface gets its own file

Time Series Management#

For time-dependent simulations:

  • Time series data is organized into separate files per time step

  • ParaView can automatically detect and load these as time series

  • The frequency of output is controlled by the Frequency setting

File Naming Convention#

Output files follow this naming convention:

  • <CaseName>_<OutputType>_<OutputName>_<TimeStep>.<extension>

Example: Aircraft_SurfaceOutput_WingPressure_00100.vtp

Note: The <OutputName> part of the filename comes from the name you assign to the output. Because the name is included in the filename as a suffix, the same surface can appear in several Surface Outputs (for example at different frequencies or formats) without their files overwriting each other, as long as each output that shares the surface has a unique name. See Surface Output for details.

Format-Specific Features#

ParaView-Specific Features#

  • Multi-block datasets for complex geometries

  • Easy visualization of vector fields

  • Extensive color mapping options

  • Streamline, particle trace, and pathline visualization

  • Volume rendering for 3D scalar fields

  • Python scripting for automation

Tecplot-Specific Features#

  • Specialized aerodynamic analysis tools

  • Advanced XY plotting

  • Integrated forces and moments calculation

  • Specialized boundary layer analysis

  • Streamtrace seeding control

  • Multi-frame layouts

File Size Considerations#

Output file sizes can vary significantly depending on:

  1. Mesh Size: Larger meshes generate larger output files

  2. Output Frequency: More frequent outputs generate more files

  3. Number of Output Fields: Each additional field increases file size

  4. Output Type: Volume outputs are typically much larger than surface outputs

To manage file sizes:

  • Be selective about which output fields to include

  • Use appropriate output frequency

  • Consider using slices or isosurfaces instead of full volume outputs

  • Use probes for tracking key variables over time

Post-Processing Workflow#

  1. Generate Outputs: Configure desired outputs in Flow360

  2. Load Files: Open the generated files in ParaView, Tecplot, or other compatible tools

  3. Visualize: Create appropriate visualizations (contours, vectors, streamlines, etc.)

  4. Analyze: Extract quantitative data, compare with experimental results

  5. Export: Save images or videos for reports and presentations

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