About seed_density model
About seed_density model
Hello, I have a question on the setting of the seed-density model. In the example, there is only random distribution for seed density, so, I wonder how to set a seed in a uniform distribution of the seed density? thanks a lot.
Re: About seed_density model
Hi Feng,
Welcome to the MICRESS Forum!
To be honest, I don't really understand your question! The idea of the seed density model is to create a (spatially) random distribution of potential seeds at the beginning of the simulation which can be activated during run-time. This is done for each class of radii thus creating a (stepwise defined) seed density function.
What do you mean with "uniform" distribution?
Best regards
Bernd
Welcome to the MICRESS Forum!
To be honest, I don't really understand your question! The idea of the seed density model is to create a (spatially) random distribution of potential seeds at the beginning of the simulation which can be activated during run-time. This is done for each class of radii thus creating a (stepwise defined) seed density function.
What do you mean with "uniform" distribution?
Best regards
Bernd
Re: About seed_density model
Hello, Bernd,
I just want to set up assumption that the particles nucleated at determined position not random distribution in the bulk, is it possible for MICRESS? thanks.
I just want to set up assumption that the particles nucleated at determined position not random distribution in the bulk, is it possible for MICRESS? thanks.
Re: About seed_density model
Hi Feng,
This is also possible in MICRESS, as "deterministic" nucleation (at critical undercooling or driving force), but not with the seed-density model!
Generally, one can define different types of locations for nucleation, e.g. bulk, interfaces (which can be further specified in manyfold ways), triple junctions and regions. The seed-density model (which is specifically for heterogeneous nucleation) can only be used (and makes only sense) with "bulk" and "region".
To specify a fix location, one can use "region" with an extend of only one numerical grid cell.
Bernd
This is also possible in MICRESS, as "deterministic" nucleation (at critical undercooling or driving force), but not with the seed-density model!
Generally, one can define different types of locations for nucleation, e.g. bulk, interfaces (which can be further specified in manyfold ways), triple junctions and regions. The seed-density model (which is specifically for heterogeneous nucleation) can only be used (and makes only sense) with "bulk" and "region".
To specify a fix location, one can use "region" with an extend of only one numerical grid cell.
Bernd
Re: About seed_density model
OK, thanks for your reply. Can I set up numbers of region in the bulk, or only one region?
Re: About seed_density model
Dear Feng,
Seeding is organized in different seed types. For each seed type, you define the location where seeding is checked, and all the other parameters like phase number, reference phase, substrate phase, critical undercooling, crystallographic orientation, shield parameter etc.
Thus, if you need more than one region, you define one seed type for each. The size of the region is defined by the min. and max. values of the x,y,z coordinates.
Seeding is organized in different seed types. For each seed type, you define the location where seeding is checked, and all the other parameters like phase number, reference phase, substrate phase, critical undercooling, crystallographic orientation, shield parameter etc.
Thus, if you need more than one region, you define one seed type for each. The size of the region is defined by the min. and max. values of the x,y,z coordinates.
Re: About seed_density model
Thanks Bernd, would you please give me an example for setting up different regions? my Micress version is 6.1, thanks a lot.
Re: About seed_density model
There is nothing special about "region": It behaves like "bulk", just, that you have to specify the minimum and maximum coordinates for the region.
The use of different seed types you can see in the standard example "Gamma_Alpha_dri". You could just take seed type No 3, replace "bulk" with "region" and add 4 lines with the minimum and maximum x and z coordinates. Then nucleation in this seed type is considered only in the specified region instead of the whole simulation domain. You can easily add others for other regions (do not forget to adjust the number of seed types at the beginning of the "Data for further nucleation" section).
The use of different seed types you can see in the standard example "Gamma_Alpha_dri". You could just take seed type No 3, replace "bulk" with "region" and add 4 lines with the minimum and maximum x and z coordinates. Then nucleation in this seed type is considered only in the specified region instead of the whole simulation domain. You can easily add others for other regions (do not forget to adjust the number of seed types at the beginning of the "Data for further nucleation" section).