simtk.org

Hi all,

I need to solve the transport of a scalar in blood flow and determine its concentration in different regions over time. I have a few ideas on how to approach this problem, which I've outlined below, but I would appreciate some external input from the code maintainers on what might be the best approach. To obtain the velocity field, I will use the solution provided by svSolver. I assume this is a diluted problem, so there is no feedback from the scalar T to the fluid.

The transport equation I am looking to solve is the following: (I think mathjax is not supported)
[math] \frac{\partial T}{\partial t} + \nabla \cdot (\mathbf{u} T) - \nabla \cdot (D_T \nabla T) = 0 [\math]

This is the simple convection-diffusion equation without sources. The methods I am considering to solve this problem are:

1. Convert the VTU solution to OpenFOAM-readable files and use scalarTransportFoam: This would involve solving the problem at each time step using OpenFOAM. However, it will require some work on setting the boundary conditions appropriately.
2. Discretize the equation using a finite element approach: I could implement the solution using VTK in C++ or Python. I believe there are tutorials and papers available on this formulation and how to implement it for unstructured meshes.
3. Implement the solution for the transport equation directly in svSolver: This option would require some guidance from the developers on how to proceed and which files to focus on. Additionally, I have no experience with Fortran programming, so I would need to learn the language. Despite this, I believe it would be the most beneficial option for the community in the long run.

I think this could be a valuable feature to implement in the future. I have compiled svSolver from source, so I am willing to contribute something directly to the solver and test it out. However, it will likely take me a month or so, given that I am completely new to Fortran. I would appreciate hearing your feedback on this and any suggestions you might have for approaching this problem. Perhaps you have a better idea!

Thanks a lot!

Best,
Ignacio

Hi Ignacio,

The svFSIplus code has support for an advection-diffusion equation, see the dye_AD example.

To simulate convection set the Coupled parameter to true Btw, any new solver development should be done in the svFSIplus code. The svSolver code will be archived soon.

Cheers,
Dave

Great! Thanks a lot for your answer. I was not aware of that solver, so thanks for pointing that out! I will switch to svFSIPlus then.

Also, while I was working on a VTK script to convert .vtu and .vtp to OpenFOAM readable meshes and velocity fields, I thought of something that may be of interest. I will open an issue on simVascular because I think it's a bug according to the guidelines of the Forum.

Thanks again!

Best,
Ignacio