Dear preCICE community,

I adapted **/tutorials-master/FSI/cylinderFlap/OpenFOAM-CalculiX** (cylinderFlap) to a square pillar with a flap. It would report the error:

—[preciceAdapter] [DEBUG] Writing coupling data…

—[preciceAdapter] [DEBUG] Advancing preCICE…

—[precice] e[0m Mapping Forces0 conservative from Fluid-Mesh-Faces (ID 0) to Calculix_Mesh (ID 2) for dimension 0) with polynomial set to separate

—[precice] e[0m Mapping Forces0 conservative from Fluid-Mesh-Faces (ID 0) to Calculix_Mesh (ID 2) for dimension 1) with polynomial set to separate

—[precice] e[0m Mapping Forces0 conservative from Fluid-Mesh-Faces (ID 0) to Calculix_Mesh (ID 2) for dimension 2) with polynomial set to separate

—[precice] e[0m Compute read mapping from mesh “Calculix_Mesh” to mesh “Fluid-Mesh-Nodes”.

—[precice] e[0m Using tree-based preallocation for matrix C

—[precice] e[0m Using tree-based preallocation for matrix A

—[precice] e[0m Mapping Displacements0 consistent from Calculix_Mesh (ID 2) to Fluid-Mesh-Nodes (ID 1) for dimension 0) with polynomial set to separate

—[precice] e[0m Mapping Displacements0 consistent from Calculix_Mesh (ID 2) to Fluid-Mesh-Nodes (ID 1) for dimension 1) with polynomial set to separate

KSP Object: Coefficient Solver (solverC_) 1 MPI processes

type: gmres

restart=30, using Classical (unmodified) Gram-Schmidt Orthogonalization with no iterative refinement

happy breakdown tolerance 1e-30

maximum iterations=10000, nonzero initial guess

tolerances: relative=1e-09, absolute=1e-50, divergence=10000.

left preconditioning

using PRECONDITIONED norm type for convergence test

PC Object: (solverC_) 1 MPI processes

type: icc

out-of-place factorization

0 levels of fill

tolerance for zero pivot 2.22045e-14

using Manteuffel shift [POSITIVE_DEFINITE]

matrix ordering: natural

factor fill ratio given 1., needed 1.

Factored matrix follows:

Mat Object: 1 MPI processes

type: seqsbaij

rows=330, cols=330

package used to perform factorization: petsc

total: nonzeros=54615, allocated nonzeros=54615

block size is 1

linear system matrix = precond matrix:

Mat Object: C 1 MPI processes

type: seqsbaij

rows=330, cols=330

total: nonzeros=54615, allocated nonzeros=54615

total number of mallocs used during MatSetValues calls=0

block size is 1

> —[precice] e[31mERROR: e[0mThe linear system of the RBF mapping from mesh Calculix_Mesh to mesh Fluid-Mesh-Nodes has not converged. This means most probably that the mapping problem is not well-posed. Please check if your coupling meshes are correct. Maybe you need to fix axis-aligned mapping setups by marking perpendicular axes as dead?

In my example, the z-axis is dead in precice-config.xml (2.7 KB) . And i adapted the **./fluid/system/blockMeshDict** and **./solid/flap.inp** to blockMeshDict.txt (6.8 KB) and flap.inp (56.2 KB) .

This is my fluid mesh:

I have check my meshes ang xml-file many times, but i can not figure out where my fault is.

How can i do to solve this?