Elmer Discussion Forum

After the refining by splitting, I recombined the triangles to quads, went 2nd order, and the all of the errors went away and a solution was obtained.

I would suspect mesh quality. I downloaded the files and ran as is and I received the numerous ERROR:: ElementMetric: Degenerate errors I did a refine by split 1 time in gmsh and that error went away I then received a non-convergence error ERROR:: ComputeChange: Numerical Error: Norm of solution app...

If your mesh is in the current directory and your number of cores specified for the solver is the same as the number of partitions then
Mesh DB "." "."

should be ok since your mesh is in the current directory.

using the ShoboxFsiEigen2d test case with Density = 2710.0 Youngs Modulus = 70e9 Poisson Ratio = 0.3 The beam frequency should be 87 Hz in air and 55 Hz in water with $ AirDensity = 1.0 $ SoundSpeed = 300 ElmerSolver reports EigenSolveComplex: EIGEN SYSTEM SOLUTION COMPLETE: EigenSolveComplex: Eigen...

The mesh location is specified in the header on the line Mesh DB "." "." This is at the top of the form in ElmerGUI setup. . . meaning current directory your mesh is in the current directory Your error.txt file reports The mesh will be partitioned with Metis to 2 partitions. mean...

I went to the test cases
HelmholtStructure
HelmholtStructure2
HelmholtStructure3

and change the density from 1 to 1000, and the sound speed from 300 to 1443.

In each one there was no difference in the structural result, but the pressure calculation changed.

and that is going to be impacted by mesh density, the finer the mesh the closer together they are. Think of the nodes as direct claculated values and the elemental as the average of all of the nodes. If the mesh is fine enough there is no difference, but it takes more computer solve the finer the me...

Regarding the 2 current densities one is data at the nodes
and the other is data at the element centroids (the one that ends in e)

"independent geometry densities between structure and fluid I can look at" In Elmer this requires the use of mortar boundary conditions. With mortar you have a master and slave so the mesh does not have to conform. Elmer Solver Manual Section 9.2 https://www.nic.funet.fi/pub/sci/physics/el...