[petsc-users] Staggered solver phase field

[Barry Smith]

   I am unfamiliar with this simulation type, so I have some elementary questions. Is each "physics" taking a fractional time-step so that the total time 
integrated (in a time-step) is 1/2dt + 1/2dt or is one physics stepping the entire time-step and the other physics "fixing up some of the variables" (for example, in fluid flow where a pressure solve doesn't step in time it merely changes some variables values to enforce incompressibility at the new time). Another way to phrase the question is are the underlying equations a DAE, not an ODE?

  Barry


> On Apr 23, 2025, at 10:20 AM, PERRIER-MICHON Augustin <augustin.perrier-michon at ensma.fr> wrote:
> 
> Dear Petsc users,
> 
> I am currently dealing with finite element fracture analysis using phase field model. To perform such simulations, I have to develop a staggered solver : mechanical problem is solved at constant damage and damage problem is solved at constant displacement.
> 
> I created 2 TS solver and 2 DMPLEX for each "physics".
> Each physics's system is built using TSSetIFunction and TSSetIJacobian with associated functions.
> 
> The TS calls are performed with TSSTEP in order to respect staggered solver scheme in iterative loops.
> 
> My question : Is the using of TSSTEP function adapted to a staggered solver ? How to use this function in my framework ? Have you got any other suggestions or advices ?
> 
> Thanks a lot
> Best regards
> 
> -- 
> Augustin PERRIER-MICHON
> PhD student institut PPRIME
> Physics and Mechanics of materials department
> ISAE-ENSMA
> Téléport 2
> 1 Avenue Clément ADER
> 86361 Chasseneuil du Poitou- Futuroscope
> Tel : +33-(0)-5-49-49-80-97