OpenLB UseCase A

In this example, we demonstrate how to simulate blood flow through a vessel using Voreen with the OpenLB integration. To get started, all you need is a .stl file representing the geometry. For this example, we use the aorta3d.stl file from the OpenLB website.

To begin, open the workspace:

The workspace ist currently not available in Voreen and will be added as soon as possible.

Once you're in the application mode, you'll see the following: For a brief introduction to the network mode, refer to Geometry Preprocessing.

Operations in the Properties space:

• Input Geometry:
  Load a geometry in .stl file format.
• Inlet/Outlet:
  Based on the FlowIndicatorDetection processor, this allows you to configure basic boundary conditions for the simulation. You can set and adjust the incoming and outgoing flow through the vessel.
• Simulation Setup:
  The processors FlowParametrizationEnsemble & FlowParametrizationRun allow provide various parameter settings for simulations. For more information, see (https://doi.org/10.2312/vcbm.20201180).
• Run Simulation & Results:
  Start the simulation, choose a location to save the results, and select the results to open them.

Simulation results

After setting the parameters, you can start the simulation and visualize the results. Here's an example:

Interaction with simulation results

The split view below the dataset enables some analysis and interaction.

Left side: Choose from three different presentations of the axial plane, each displaying different information: geometry, velocity, and boundary conditions. When hovering over the visualization, each plane shows voxel positions and data values. In the velocity plane, press ctrl to draw a line, which can be analyzed on the right side.
Right side: The line drawn in the velocity plane is displayed as a 2D graph, showing the velocities along the line and linearly interpolating between points.

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Geometry Preprocessing

Processor Operations

• GeometrySource: Load a geometry in a .stl file format.
• GeometryTransformation: Apply a transformation matrix to the loaded geometry when enabled.
• GeometryClose: Close holes in the geometry up to a certain thickness when enabled.
• GeometrySmoothNormals: Smooth geometry artifacts when enabled.
• GeometryInsideTest: Convert the geometry to a volume so that the VesselGraphCreator can be applied.
• VesselGraphCreator: Create a vessel graph as described in Vessel Graph Extraction
• FlowIndicatorDetection: Configure conditions needed for the simulation, such as analyzing the vessel graph to define inlets and outlets.
• FlowParametrizationEnsemble & FlowParametrizationRun: Provide various parameter settings for simulations.
• FlowSimulationCluster & FlowSimulation: Processors for creating simulations.