[deal.II] Incompressible fluid with fully periodic boundary conditions

Hi, I'm a kind of new user of dealii and I'm trying to set up the boundary conditions for a domain [0, 1] X [0, 1] of incompressible fluid with fully periodic boundary conditions. I know that for an incompressible fluid with fully periodic boundary conditions (velocity both directions and press

[deal.II] Problem with Block Preconditioner and Fully Periodic Boundary Conditions

Hi, any chance I could get your help with that? I'm trying to use the code of @Jie-Cheng for Block Preconditioner (https://github.com/dealii/code-gallery/tree/893bdb5b0a770758fce98859ab4d137f95e62a50/time_dependent_navier_stokes) for a case of fully periodic b

[deal.II] Re: Problem with Block Preconditioner and Fully Periodic Boundary Conditions

Hi Daniel, thank you for replying. I have looked thoroughly step 45 but it's not of much help for my case. I actually want to impose periodic boundary conditions for both velocities and pressure (I need to have a representative periodic cell). I used the following lines to set pressure to zero

Re: [deal.II] Re: Problem with Block Preconditioner and Fully Periodic Boundary Conditions

Hi Wolfgang, thanks for the reply. I'm working on Immersed Boundary Method and flagella swimming, and, more specifically, I'm trying to model a unit square domain, which is infinitely replicated in two dimensions, governed by the incompressible time-dependent stokes equations for low Reynolds n

Re: [deal.II] Re: Problem with Block Preconditioner and Fully Periodic Boundary Conditions

Hi Wolfgang, that's exactly the problem, B has rank much less than the number of columns which is due to the fully periodic boundary conditions and the corresponding sparsity pattern. So I don't know how I could solve this issue. Any ideas? Best, Magda On Wednesday, January 16, 2019 at 7:31:5

Re: [deal.II] Re: Problem with Block Preconditioner and Fully Periodic Boundary Conditions

Hi Daniel and Wolfgang, When I apply periodic boundary conditions only on velocities at all the four sides of my unit square domain, then the rank of B (mxn) becomes rank(B) = n-1, which I think is as you say due to the fact that the pressure is up to a constant . However, when I try to impose

[deal.II] Problem with "constraints.distribute_local_to_global(local_rhs, local_dof_indices, system_rhs)"

Hi, I want to assemble my system matrix only once since it doesn't change throughout the time steps. For that my code is similar to step-57: if (assemble_matrix){ constraints.distribute_local_to_global(local_matrix, local_rhs, local_dof_indices, system_matrix, system_rhs); } else{ cons

Re: [deal.II] Problem with "constraints.distribute_local_to_global(local_rhs, local_dof_indices, system_rhs)"

/20 9:24 AM, Magdalini Ntetsika wrote: > > > > but I don't seem to get the same *system_rhs *when > > *assemble_system=false* as when *assemble_system=true*. To be more > > specific, it seems that there is something wrong with how > > constraints.distribut

Re: [deal.II] Problem with "constraints.distribute_local_to_global(local_rhs, local_dof_indices, system_rhs)"

t; Daniel > > Am Do., 5. März 2020 um 16:13 Uhr schrieb Magdalini Ntetsika < > ntet...@berkeley.edu >: > >> Hi Wolfgang, >> >> thank you for the prompt reply. I see, I'll look up both. But I have a >> quick question: what if I have periodic boundary condi