Mesh refinement error

[brasp]

Hello,

I am simulating the water level in a ditch. I want to insert a mesh refinement at the ditch boundaries and at the atmospheric boundary. When I insert a refinement of 33cm, everything goes well. When I apply a refinement of 1cm, I always got an error 'Error No. 13 during the generation of 2D mesh, Fundamental triangulation failed: Surface No. 3, Edge No 43.' The yellow array does not really point to a specific point of my geometry. Can you have a look to my attached simulation?

Thanks in advance!

[Mirek]

Hi,
your domain is almost 20000 cm long and the required mesh density is simply too high (element size 1 cm), The ratio is greater than 1:10000, which is the reason why the mesh generation fails. If there is a real need to use such a dense mesh, then it is necessary to use some tricks - see Figure 1 and fixed project in Mesh1.zip. However, for this project it would seem more appropriate to use "Mesh stretching" - see attached Figure 2 and project in Mesh2.zip.

Mesh1.jpg (862.64 KiB) Viewed 21650 times

Figure 1

Mesh2.jpg (910.03 KiB) Viewed 21650 times

Figure 2

[brasp]

Thanks Mirek for your elaborated answer!

The mesh generation worked well! When I want to run the simulation, I get immediately the error 'ORTHOMIN terminates - too many iterations'. I tried to lower the hCritA and additionaly lowered the water content tolerance and pressure head tolerance. Nevertheless, the error remains. Do you know how to bypass this calculation error?

Thanks a lot!

[Jirka]

See FAQ3: https://www.pc-progress.com/en/Default. ... q-01-10#k3. J.