[FLASH-USERS] Possibility of restarting FLASH from a selected region

[Seyit Hocuk]

Dear Kevin,

I am using FLASH 2.5 still. However, 50! levels? That's insane :).
Refining is especially interesting (my opinion) if you do structure/star 
formation where you have a core collapse and the density, temperature 
and pressure increases thereby reducing the timestep. In effect, for me, 
I can not go beyond level of ~10 refinement. However, starting from a 
smaller boxsize (in a specific region) would make it possible to do the 
same resolution (say 10) and result in a detailed image of that area. Of 
course, refining only this selected region and adapting the mesh from 
10-20, is more ideal (boundary conditions and stuff), it is much more 
computer demanding (even though the number of blocks do not seem 
increase much) and impossible to achieve for me.

I have the impression that other codes, like ENZO, can do this more easily.

Kind Regards,
Seyit



Kevin Olson wrote:
> Dear Seyit,
>
> What version of FLASH are you using?  If you are using version 3.0 or 
> above then you can refine up to 50 levels.
>
> I don't think FLASH supports specifically what you are asking for.  
> You could try just keep the computational domain as it is, derefine in 
> the regions where you are not interested and refine in the region 
> where you are interested.  An advantage of doing this is that the 
> original boundary conditions in your refined regions will be 
> preserved.  A disadvantage is that the floating point computations may 
> loose accuracy.
>
> Best,
> Kevin Olson
>
> On Mar 12, 2009, at 9:15 AM, Seyit Hocuk wrote:
>
>> Hi Community,
>>
>> I was wondering if it is possible to start a new Flash simulation 
>> from an end point of an older simulation by just selecting a part of 
>> the data, perhaps by a child block/level. This would now be the top 
>> block and act as the new initial conditions, forgetting everything 
>> else. I hope I am being clear in this. This way we could go much 
>> higher in resolution, without increasing the computational demands, 
>> by zooming in on an area and restarting simulation from there.
>>
>> Thanks,
>> Seyit
>>
>