Discussion Forum

Hi

it's most probably because you have FSI which contains "structural solid" physics and "Solid" physics in the same model. You are duplicating many features, and if you do not use different dependent variable names you might get "duplicated names" error. Still the names on the list are puzzling, they are coordinates and not dependent variables.

Anyhow, with FSI normally you do not need to add solid, as its already contained in FSI, under subsection Structural

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Good luck
Ivar

I've decided to just use FSI. Now I get this error : "Failed to create temporary file on server." Any ideas?

Thanks,
Jim

Hi

that depends on the installation, COMSOL needs to store temporary files somewhere (check the release notes)

It might store in a user defined scratch region, in your ...user ... temp location or for your case on a server somewhere. This location might get clogged up (depends on Comsol version) and might need to be cleaned up a bit ;)

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Good luck
Ivar

How do change where these temp files are stored in COMSOL? Can't find it in the release notes. Any ideas?

Jim

Hi

Then Check the KB (Knowledge Base of the main site above) as well as the forum (try a search on "temporary files") this was discussed and I believe top remember that one of the COMSOL employees gave some hints here on the Forum some weeks ago

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Good luck
Ivar

Thank you! I have fixed that problem. I am getting an error saying "Detail: mod1.fsi.vWallx, mod1.fsi.vWally." Yet I filled in all that was asked for. Any advice would be very much appreciated.

Jim

Hi

that means you have chosen turbulent mode and use wall variables, and something is not well set up, take a closer look on the main physics node of the fluid solid interface

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Good luck
Ivar

Hmm, I selected "None" for "Turbulence Model Type" and everything else looks okay. I selected both the fluid and solid domains in the FSI's main node, but it does not allow me to select the boundaries under "Fluid-Structure Interface Boundary," labeling all of them as "not applicable." What to make of this?

Thanks
Jim

Hi, in FSI you have a main node for all domains (fluid + solid) and then you have two sub nodes, one for the fluid only and one for the solid (you might need to add one of these two manually, it might not be there by default). Then you "wall" is set up as default for the I/F boundaries between the fluid and solid. You may add several nodes and also the same nodes, if you have different materials or physics to apply, on the boundary nodes ^some are additive some are exclusive (check the icons and the doc)

An entity (domain or boundary) that is tagged "(overridden)" has simply been redefined by another node further own the tree model. An Entity tagged "(not applicable)" does not fit the physics selected or is not related to the specific physics.

one need to get used to this chaining and potential overriding of properties, but it is very handy for multiple cases studies. one can add or disable a later node and change the simulation case simply and rapidly. In next release I hope COMSOL manages to have these disable/enable also driven by the different solver selected

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Good luck
Ivar

Hi,

COMSOL automatically identifies the boundaries that form the fluid-solid interface. In the model both domains seem to be defined as fluids. A first step here is to add, for example, a Linear Elastic Material Model node to domain 2 to represent the solid. The boundary selection in the Fluid-Solid Interface Boundary node is then updated to include the four boundaries that separate the solid from the fluid.

Best regards,
Magnus Ringh, COMSOL

I appreciate all the help. I have one more error: "Failed to find consistent initial values.
Last time step is not converged." My initial conditions seem to be ok. Might it be something else?

Thank you,
Jim

Hi all,

I am getting the same error (but 42 errors instead of just 28) when I involve "ale" in simulating the basic electrostatic actuation problem of a cantiever. Is it possible to help me get rid of this message?

I downloaded a file from COMSOL called "ale_cantilever_beam_3d", and I just follow what it does with my own switch (except for the symmetry part), but I keep getting the error message described above. In fact, I use Moving Mesh, Solid Mechanics and Electrostatics modules together.

Thank you very much for your help and time.

Looking forward to read your valuable feedback.

Ahmed