Search found 99 matches
- 10 May 2012, 22:12
- Forum: ElmerSolver
- Topic: MATC enthalpy def for phase change breaks latent heat check
- Replies: 22
- Views: 22512
Re: MATC enthalpy def for phase change breaks latent heat check
since the Temporal part works fine, the problem is getting past the Spatial_1 part. This part needs a local derivative (dH/dT), which I guess is hard to guess at numerically for data that isn't definitely piecewise linear. Hence the ListGetDerivValue calls DerivateCurve which uses the points in a ta...
- 10 May 2012, 19:58
- Forum: ElmerSolver
- Topic: MATC enthalpy def for phase change breaks latent heat check
- Replies: 22
- Views: 22512
Re: MATC enthalpy def for phase change breaks latent heat check
I'll just keep a running commentary here: tracing back the function call, the main problem I see: !------------------------------------------------------------------------------ !> Gets a real derivative from. This is only available for tables with dependencies. !------------------------------------...
- 10 May 2012, 19:38
- Forum: ElmerSolver
- Topic: MATC enthalpy def for phase change breaks latent heat check
- Replies: 22
- Views: 22512
Re: MATC enthalpy def for phase change breaks latent heat check
ok, put a bunch of breaks in at the various points it pulls enthalpy/heat capacity. it appears the problem is within the EffectiveHeatCapacity subroutine. the first time through the transient model, because there is no previous timestep, even with Phase Change Model = 'Temporal' it instead uses 'Spa...
- 10 May 2012, 19:15
- Forum: ElmerSolver
- Topic: MATC enthalpy def for phase change breaks latent heat check
- Replies: 22
- Views: 22512
Re: MATC enthalpy def for phase change breaks latent heat check
some more info. Trying to debug, I grabbed the HeatSolve.scr and inserted a Pause at 1191 inside the IF after checking for the condition to reduce the timestep. I had it print out the nodal temperatures and the temps from the previous time step. When using the adaptive stepping, and the enthalpy tab...
- 10 May 2012, 19:11
- Forum: ElmerSolver
- Topic: fortran user function: how to use variable (SaveData Target)
- Replies: 13
- Views: 9989
Re: fortran user function: how to use variable (SaveData Target)
well, he said he's getting the error on attempting to read in the value: ! read in var var = ListGetConstReal( Model % Simulation, 'var', found) IF(.NOT. found) THEN CALL Fatal ( 'myFunction', 'var not found') END IF I assumed he meant he was having trouble with syntax and was getting the 'var not f...
- 10 May 2012, 18:27
- Forum: ElmerSolver
- Topic: fortran user function: how to use variable (SaveData Target)
- Replies: 13
- Views: 9989
Re: fortran user function: how to use variable (SaveData Target)
First thought, you named your variable "Variable 4" not 'var'. I just did a UDF where I had constants defined in the Material section, and then pulled them into the UDF. I used the following lines in the Material section to define them: ENTH1 = Real $E1$ ENTH2 = REAL $E2$ enth1 = GetConstR...
- 09 May 2012, 18:09
- Forum: ElmerSolver
- Topic: MATC enthalpy def for phase change breaks latent heat check
- Replies: 22
- Views: 22512
Re: MATC enthalpy def for phase change breaks latent heat check
playing around with this more, tried making a UDF to do the same thing. here's the modified Materal section with all 3 options Material 1 Name = "PCM" Density = $rhos$ Heat Conductivity = $kths$ !simple linear enthalpy change !Enthalpy = Variable Temperature ! Real ! 0.0 0.0 ! $T1 E1$ ! $T...
- 07 May 2012, 23:22
- Forum: ElmerSolver
- Topic: MATC enthalpy def for phase change breaks latent heat check
- Replies: 22
- Views: 22512
MATC enthalpy def for phase change breaks latent heat check
so "Check Latent Heat Release = true" turns on an adaptive time stepping routine that will reduce the timestep by half and then reruns the timestep if it detects that the phase front has moved farther than a single element. If I use a table to define enthalpy, this works well. It runs 50 t...
- 07 May 2012, 22:44
- Forum: ElmerSolver
- Topic: Heat Flux BC in 2D mesh
- Replies: 5
- Views: 5263
Re: Heat Flux BC in 2D mesh
just for completeness, here's an example BC block from one of my heat flux BC runs: Boundary Condition 4 Target Boundaries(1) = 4 Name = Cooling Heat Flux BC = True Heat Transfer Coefficient = $htc$ External Temperature = 100 End That has a constant value for the HT Coefficient (a variable defined e...
- 07 May 2012, 22:35
- Forum: ElmerSolver
- Topic: Heat Flux BC in 2D mesh
- Replies: 5
- Views: 5263
Re: Heat Flux BC in 2D mesh
Heat Flux BC is generally set to True or False. Then if it's True it looks for either a Heat Flux = "x" or a Heat Transfer Coefficient = "x". In addition, when applying a Heat Transfer Coefficient, I've also always used an "External Temperature = x " keyword to complete...