Creation of CFD User Guide

[justran-csuf]

Problem

General SimVascular users are unfamiliar with basic concepts of CFD and have trouble using svSolver and svMultiPhysics. This leads to a large volume of user questions on the forums that could be more efficiently answered by a section of documentation.

Solution

Creation of a new section of the documentation that outlines basic concepts of CFD. Some topics include:

1. Basics of the Navier-Stokes equations and how it is used to model blood flow
2. Basics of finite element discretization (i.e. how meshing works and how it affects the solution)
3. Boundary condition selection and specification (inflow, outflow, and wall conditions)
4. Selection of time marching parameters and explanation of solution stability
5. Basics of numerical linear solvers (i.e. selection of settings, interpreting residuals, etc.)
6. Assessing simulation results for accuracy and reliability
7. Basic CFD post-processing in Paraview (i.e. viewing solution contours, creating velocity glyphs/streamlines, model clipping, etc.)
8. Basics of using HPC resources (i.e. parallel computing, selection of compute resources, using the gateway, etc.)

List of topics will be updated as content is created and new issues arise!

Additional context

Creation of short video lessons on the above topics to provide further explanation/demonstration also is planned for the future.

Code of Conduct

• I agree to follow this project's Code of Conduct and Contributing Guidelines

[justran-csuf]

Please forward any forum posts with questions about CFD to this issue so that I can address them in the documentation as well.

[ktbolt]

@justran-csuf Your outline is excellent !

Note that some of the topics you mentioned (e.g., 5.) might could be separate and more detailed sections in the User Guide that you would just reference from your section. But it is not clear when those other User Guide sections will be written so include as much detail as you think is needed and we can move some of that to other sections later.

[justran-csuf]

Here is my current draft of the User Guide: Link to Google Docs

[ktbolt]

@justran-csuf A good start ! The CFD User Guide should only describe how to set up and run a CFD simulation using svMultiPhysics; your intro seems a bit more like a general CFD guide; we will have to give it some thought about how much background material is needed.

[justran-csuf]

Thanks for the feedback! I did want to provide more background information here to assist with the general CFD questions that often come up on the forums, especially considering most of our users have never taken a class in fluids/CFD or have much experience with CFD. But I can definitely make it a more streamlined guide on using svMultiPhysics if that is the preferred direction.

[ktbolt]

@justran-csuf Good point about users who don't have much CFD experience. The svMultiPhysics section should assume a certain level of fluids/CFD knowledge. A brief CFD Into would be good just to provide context for later content. There is a Theory section that can provide some useful concepts; that section could be improved with more finite element background.

[justran-csuf]

@ktbolt There already appears to be documentation on the SV website on how to set up a simulation in svMultiPhysics: https://simvascular.github.io/documentation/multi_physics.html (about halfway down the page is the cylinder example but it appears to be repeated twice). Did we want to use this cylinder tutorial in the User Guide or do a tutorial with a vascular model?

[ktbolt]

@justran-csuf The SimVascular MultiPhysics Tool Tutorial describes how to use the GUI; there is not really any details about the parameters and such.

I think it would be better to use the aorta with iliac arteries Demo Project.

I do indeed see that the SimVascular MultiPhysics Tool Tutorial is duplicate ! It looks like a cut-paste error by yours truly when adding the User Guide section; I will fix that. Thanks for pointing that out !