ENH : Stabilization via artificial viscosity

[KikeM]

• Remove alpha from the parameter vector (it does not belong to the problem parametrization).
• Run several FOM simulations for different values of it and analyse what changes.
• Read https://github.com/KikeM/msc-literature-review/issues/38

This could be studied together with #45.

[KikeM]

Looking at a parametric sweep for multiple alpha values, ranging from 1e-1 to 1e-11, I find out that all of them except the last two are dissipative.

However, all of them have the same error in the mass check.

This data seems to points towards the fact that I should use 1e-10. Let's cross fingers and hope for the best when it comes to the SVD of the stiffness matrix. I might need to refactor to apply the diffusion coefficient only at the end, once the FOM/ROM operator has been assembled.

Actually I might just do that straight away, to make sure I don't run into problems in a couple of days.

[KikeM]

I have just run a simplified HROM to see if such a small diffusion coefficient would endure the SVD and the thetas calculation ... and it did! :D

yeah! 😎

Let's put all the above nice and clean in the thesis draft and keep moving.