[petsc-users] Fluid-Structure interaction with multiple DMPlex

[Jed Brown]

Thibault Bridel-Bertomeu <thibault.bridelbertomeu at gmail.com> writes:

> However if you use IMEX for strong coupling of the two physics solved in
> each field, then it means you need to write a single set of PDEs that
> covers everything, don’t you ?
> If I want to solve Euler equations in one PetscDS and heat equation in the
> other one, then I need to write a global set of equations to use the IMEX
> TS , right ?

Yes.

You can use multirate integrators, which are like subcycling while controlling splitting error. Most subcycling approaches will limit your global convergence to first order in time. First order with a very small coefficient ("weak coupling") might be okay, but you do need to quantify it for each physical regime and resolution.