Elmer Discussion Forum

Hi, I have now implemented a UDF for the effective heat capacity which just computes a derivative of the specific enthalpy and multiplies that one by density. It seems that indeed this was the route to success - my simulation runs now, I will see what result I get. :) Solid density... liquid densit...

since the "normal" heat capacity in Elmer is per unit mass yeah, I remember stumbling upon that when I started using the enthalpy definitions. Heat Capacity is actually Specific Heat Capacity (but isn't named such. is there such a keyword?) Enthalpy is volumetric, not specific enthalpy, w...

ok, peter had said he added a number of new warnings related to some of the things that popped up earlier in this thread. Possible that's one of the new ones, haven't looked at the changes myself yet. Spatial 1 needs one of two things: (1) a table based Enthalpy curve. ('specific enthalpy' gets hand...

1 - what error are you getting? I've been able to do the UDF fine since I last posted about this. have you tried a 'dummy enthalpy profile', equivalent to a constant heat capacity or something to see if it's a problem with your function or the implementation? 2 - In 'theory', if you provide an entha...

just updated from 6.2 to 7.0. noticed that everywhere I used to be able to issue a "elmersolver mymodel.sif" command I now get an ERROR:: ElmerSolver: Unable to find ELMERSOLVER_STARTINFO, can not execute. since when running a single file, the only point of that startinfo file is to list t...

I have not understand this : "increasing mesh will improve accuracy up until you start hitting numerical rounding errors". Ok, looks like it does not apply to this case, but it is physically possible to overmesh your solution. But what I was referring to is the point where the elements ge...

Was it just Lists.src that was changed? i'll pull and recompile that and any other from the trunk so I don't have to pull the whole fresh install (running off windows). or not. any tips for those of us relying on the elmerf90 script on recompiling a mod file as opposed to just a solver dll? hoping ...

Was it just Lists.src that was changed? i'll pull and recompile that and any other from the trunk so I don't have to pull the whole fresh install (running off windows). So right now EffectiveHeatCapacity (spatial 1) only works for an Enthalpy table or an "Effective Heat Capacity". Transien...

In Finite Element Analysis there are several potential sources of error. A lot depends on what kind of model you're running. At its simplest, increasing mesh will improve accuracy up until you start hitting numerical rounding errors. At that point the solution can go chaotic and severely diverge fro...

end of the narrative: using either a MATC or UDF defined "Effective Heat Capacity" fixes the problem. It allows adaptive time stepping to be used with arbitrary enthalpy profiles. Running the linear test as above all three ways both with and without "Check Latent Heat Release" wo...