VI-Suite v0.6 – Basic OpenFOAM analysis

Hello again.

I’ve just uploaded a video on how to use the FloVi component of the VI-Suite to conduct an air-flow simulation with OpenFOAM. The FloVi component only currently works on Linux, and I have only tested it on Arch Linux, but it should work on other Linux distributions.

A FloVi analysis requires as a minimum a manifold mesh object to act as a CFD domain. Additional manifold mesh objects can be added within the domain but geometries cannot overlap as this is not supported by Netgen.

There was a bug in the symmetry boundary specification which I fixed a few days ago so make sure you have a recent version of the VI-Suite v0.6 from github.

The example I show in the video is of a domain with ground terrain making up one of the boundary surfaces. If a building is to be modelled that touches the ground plane then one way is to extrude the shape up from the ground boundary. This way the skin of the building becomes a continuation of the domain boundary.


Extrusion from the ground plane

Another way is to add the building geometry as CFD geometry, but as said earlier this cannot overlap with the domain boundary. One way to get round this is to remove the ground plane that the building sits on, and then fill the edges between the bottom of the walls and the bottom edges of the domain.

A third way is to do a boolean difference between the CFD domain and the building geometry. The example below shows a boolean difference operation between the domain and an overlapping torus, which leaves the torus shape as a perturbation to the ground plane.

Boolean difference

Generating boundary geometry with a boolean difference

FloVi is experimental and generally works for me, but is not meant to intelligently apply boundary conditions for you. That is a manual process, and you should know what boundary conditions are appropriate for the simulation context you have. If the interface does not write out the correct boundary information based on your input then file a bug report at the github page and if there are additional boundary conditions you want added to the interface then post a request on the Google Group.

The default OpenFOAM solver I use in the video is simpleFOAM, and this is the one I’ve got working fairly reliably.

Finally, although the VI-Suite itself cannot visualise OpenFOAM results there is another another Blender node-based addon called BVTKNodes that can open OpenFOAM meshes and results and I have had some joy visualising results with it, so check it out if you want a complete Blender workflow.

That’s it I think. As ever, video below.