[petsc-users] Is fieldsplit suitable for compressible Navier-Stokes?

[Song Gao]

Dear PETSc users,

We are solving a FEM compressible Navier-Stokes problem. The unknowns are
arranged as [ rho1, rho1*u1, rho1*v1, rho1*w1, e1, .....  ]. We are using
ASM+ILU(0) but  I'm playing with fieldsplit preconditioner to assess its
advantages. After some search, I found most of the fieldsplit examples are
for Stockes flows or incompressible Navier-Stokes. Is there any
compressible Navier-Stokes example?

I tried to run with options
-ksp_view -ksp_monitor_true_residual -ksp_converged_reason -ksp_max_it 1000
-ksp_gmres_restart 400 -ksp_type fgmres
-pc_type fieldsplit -pc_fieldsplit_block_size 5 -pc_fieldsplit_0_fields 0
-pc_fieldsplit_1_fields 1,2,3 -pc_fieldsplit_2_fields 4
-pc_fieldsplit_type additive
-fieldsplit_0_ksp_type gmres -fieldsplit_0_ksp_monitor_true_residual
-fieldsplit_0_ksp_max_it 20 -fieldsplit_0_pc_type bjacobi
-fieldsplit_0_sub_pc_type ilu
-fieldsplit_1_ksp_type gmres -fieldsplit_1_ksp_monitor_true_residual
-fieldsplit_1_ksp_max_it 20 -fieldsplit_1_pc_type asm
-fieldsplit_1_sub_pc_type lu
-fieldsplit_2_ksp_type gmres -fieldsplit_2_ksp_monitor_true_residual
-fieldsplit_2_ksp_max_it 20 -fieldsplit_2_pc_type bjacobi
-fieldsplit_2_sub_pc_type ilu


The residual history is attached. ,The velocity field failed to converge
even though I used ASM+LU for this field. Any suggestions? Thanks in
advance.


Song Gao
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