Search found 1505 matches

by Bernd
Tue Oct 06, 2009 10:05 pm
Forum: solidification
Topic: Averaging of driving force
Replies: 3
Views: 2931

Re: Averaging of driving force

It is like you say: the local phase-field gradient is randomly rotated with a maximum amplitude of the given angle (in degrees), in 3d along three axes. This procedure is done for each interface cell independently, i.e. for each cell a complete path through the interface is calculated. There is no l...
by Bernd
Tue Oct 06, 2009 8:24 pm
Forum: solidification
Topic: Averaging of driving force
Replies: 3
Views: 2931

Re: Averaging of driving force

Dear Nils, you are raising a difficult question about these "dG options" which are all "dirty" parameters in terms of a scientifically pure phase-field model. I already tried to explain part of your query in this thread , maybe you have already read it. The question which remains open is how to use ...
by Bernd
Tue Oct 06, 2009 7:49 pm
Forum: pre-processing
Topic: concentration initilization
Replies: 5
Views: 4287

Re: concentration initilization

Hi, MICRESS is able to read the initial concentration fields either from an ASCII profile or a 2/3-dimensional ASCII array file. The input could e.g. look like that: # # Initial concentrations # ====================== # How shall initial concentrations be set? # Options: input equilibrium from_file ...
by Bernd
Fri Oct 02, 2009 2:56 pm
Forum: phase-field model
Topic: 1d_temp
Replies: 11
Views: 14235

Re: 1d_temp

What is 1d_temp option and in which part of the driving file it appears? In a calculation domain, how nonlinear temperature gradient could be defined by “1d_temp” option? Which data each column of the file containing one-dimensional temperature field represents? Dear mtoloui, I just implemented a g...
by Bernd
Mon Sep 28, 2009 10:01 pm
Forum: phase-field model
Topic: 1d_temp
Replies: 11
Views: 14235

Re: 1d_temp

Dear sunny, if you want to setup a simulation like e.g. the one illustrated by the "AlCu_Temp1d_dri" example, of course, you need physical parameters like the heat diffusivity and the thermal boundary conditions which correspond to your process. Furthermore, especially if phase transformations are s...
by Bernd
Mon Sep 28, 2009 9:06 pm
Forum: solidification
Topic: One problem about latent heat
Replies: 2
Views: 4714

Re: One problem about latent heat

Dear sunny, the example you are referring to is probably from Version 5.3. From Version 5.4 we decided to calculate latent heat directly from the thermodynamic database used in the example which is much better and easier. Combining coupling to thermodynamic data with manual input of latent heat data...
by Bernd
Thu Sep 17, 2009 4:03 pm
Forum: phase-field model
Topic: some numerical consequences
Replies: 3
Views: 2938

Re: some numerical consequences

Hi zhubq, I am a bit astonished that you really need 10 cells interface thickness to get a reasonable shrinkage of a sherical grain! Did you check whether there are other parameters which could cause the trouble? Did you try a smaller time step or a smaller phMin? If you wish you can paste or send t...
by Bernd
Fri Sep 11, 2009 2:17 pm
Forum: pre-processing
Topic: Initial Microstructure
Replies: 7
Views: 4525

Re: Initial Microstructure

Yes, it should. I never tried it personally, but it should!

Bernd
by Bernd
Thu Sep 10, 2009 6:53 pm
Forum: phase-field model
Topic: some numerical consequences
Replies: 3
Views: 2938

Re: some numerical consequences

Dear zhubq, I know from test calculations in our house that the shrinkage of a circular grain by curvature worked well and gave the correct kinetics! Most probably, there are some parameters which are not properly set. Without seeing the driving file you used I can only suspect - I have two ideas wh...
by Bernd
Thu Sep 10, 2009 5:54 pm
Forum: pre-processing
Topic: Initial Microstructure
Replies: 7
Views: 4525

Re: Initial Microstructure

No, you should not use the gradient condition for concentration in this case!

Bernd