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Got the error "Failed to find consistent initial values" when using ALE

Posted Mar 11, 2011, 5:46 p.m. EST Studies & Solvers Version 4.0 3 Replies

Xiaoyi Yu
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My model is a solidification problem contains Moving Mesh (ale) and Heat Transfer (ht) physics. The model worked well when only Heat Transfer (ht) physics was used, when I added the Moving Mesh (ale) physics, an error occurred, "Failed to find consistent initial values. Singular matrix" at the very beginning of solving. Does this error means that too large deformation of the mesh happened which lead to no convergence?
the model file was attached.

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3 Replies Last Post Mar 13, 2011, 6:25 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 12, 2011, 5:18 a.m. EST
Hi

it's related to the early version 4.0, when I load it into my 4.1 I delete the solution and run it, it starts to solve but then crashes comsol fully ;) translations not 100% OK

But you are asking the system to be slightly schisophrenic there by having the initial conditions of the domain at -20°C and then its border at 0°C

--
Good luck
Ivar
Hi it's related to the early version 4.0, when I load it into my 4.1 I delete the solution and run it, it starts to solve but then crashes comsol fully ;) translations not 100% OK But you are asking the system to be slightly schisophrenic there by having the initial conditions of the domain at -20°C and then its border at 0°C -- Good luck Ivar
Xiaoyi Yu
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Posted: 1 decade ago Mar 12, 2011, 10:46 a.m. EST

Hi

it's related to the early version 4.0, when I load it into my 4.1 I delete the solution and run it, it starts to solve but then crashes comsol fully ;) translations not 100% OK

But you are asking the system to be slightly schisophrenic there by having the initial conditions of the domain at -20°C and then its border at 0°C

--
Good luck
Ivar


What is "schisophrenic" ?
I think the initial temperature values are no problem, because the model can work when involved only Heat transfer physics. The reason that makes me think of "too large mesh deformation" is that when I use the ALE method, I often encounter this Error "Failed to find consistent initial values", especially when the moving boundary is a little bit complex, and sometimes I can fix it by some tricks, like refine the mesh.
[QUOTE] Hi it's related to the early version 4.0, when I load it into my 4.1 I delete the solution and run it, it starts to solve but then crashes comsol fully ;) translations not 100% OK But you are asking the system to be slightly schisophrenic there by having the initial conditions of the domain at -20°C and then its border at 0°C -- Good luck Ivar [/QUOTE] What is "schisophrenic" ? I think the initial temperature values are no problem, because the model can work when involved only Heat transfer physics. The reason that makes me think of "too large mesh deformation" is that when I use the ALE method, I often encounter this Error "Failed to find consistent initial values", especially when the moving boundary is a little bit complex, and sometimes I can fix it by some tricks, like refine the mesh.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 13, 2011, 6:25 a.m. EDT
Hi

It was just my comment about an initial boundary value of "0" while the domain has a Temperature of "-20" One could assume that the boundary is either at the temperature of the body=domain, or somewhere intermediate, anyhow there should come a gradient. But I agree, as initial conditions it should hold and be OK.

The other point is that I had no ALE in the model I looked at ? is ALE or a "level set" method the most appropriate for phase changes ? I'm not sure this no my usual physics domain so I'm also learning ;)

--
Good luck
Ivar
Hi It was just my comment about an initial boundary value of "0" while the domain has a Temperature of "-20" One could assume that the boundary is either at the temperature of the body=domain, or somewhere intermediate, anyhow there should come a gradient. But I agree, as initial conditions it should hold and be OK. The other point is that I had no ALE in the model I looked at ? is ALE or a "level set" method the most appropriate for phase changes ? I'm not sure this no my usual physics domain so I'm also learning ;) -- Good luck Ivar

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