[FLASH-USERS] Continuing to evolve particles that leave the domain

James Guillochon jfg at ucolick.org
Sat Mar 28 13:16:56 EDT 2015


Hi Anshu, evolution of the particles is done via the Sinks module
currently, which seems to have its own routines for evolving the particles.
At the moment I am not using the sink functionality (removing gas from the
grid), but in principle it's something I'd like to be able to do in the
future, which is why I'm using that module rather than just the active
module.

Anyway, if we ignore the sink functionality for now, I guess I'm not
understanding why my current solution isn't working. Right now when the
LOST flag would be applied, I instead just assign it to the first block on
a processor within gr_ptLocalMatch:

if(outside)blockID=gr_ptBlkList(1)

I've also tried assigning it to its original block, which doesn't work
either. And I make sure that the LOST flag is not applied in gr_ptOneFaceBC
(I just comment out the "particle(gr_ptBlk)=LOST" line).

Otherwise, there are no other locations in the code where particles can be
marked as "LOST", as far as I can tell. Particles can be marked as
"NONEXISTENT," but if this is happening I would think the particles
wouldn't even be saved in the lost list, which would be a bug.

My guess would be is that the Sinks module is doing something else that is
removing particles that leave the domain?

On Sat, Mar 28, 2015 at 12:38 PM, Anshu <adubey at lbl.gov> wrote:

> Try adding another category such as OUTSIDE, with that particle should not
> get deleted.
> Give it a number > maxblocks so that sort puts those particles at the end.
> When you pass the data structure to particle routines make sure the local
> count is such that these particles are not
> processed. And then add a routine to treat them separately. It has been a
> couple of years since
> I worked with this code, so I might have a few things wrong and a few
> details missing, but I think
> in general this should work.
>
> Best,
> Anshu
>
> On Mar 28, 2015, at 9:16 AM, James Guillochon <jfg at ucolick.org> wrote:
>
> Hi all,
>
> I'm having a bit of trouble getting this to work. I need to leave a
> particle assigned to a block at all times, and not marked as NONEXISTENT or
> LOST, resulting in its deletion. Unfortunately it seems like there's a
> number of places where particles can be mark as NONEXISTENT in the code,
> and changing them all seems difficult (there's a only a few places where
> the particle is marked as "LOST", which I've disabled).
>
> Anyone have any additional insight here? At the moment, particles are
> deleted as soon as they leave the domain, even with the changes I've made.
>
> Thanks,
> - James
>
> On Sat, Mar 28, 2015 at 12:15 PM, James Guillochon <guillochon at gmail.com>
> wrote:
>
>> Hi all,
>>
>> I'm having a bit of trouble getting this to work. I need to leave a
>> particle assigned to a block at all times, and not marked as NONEXISTENT or
>> LOST, resulting in its deletion. Unfortunately it seems like there's a
>> number of places where particles can be mark as NONEXISTENT in the code,
>> and changing them all seems difficult (there's a only a few places where
>> the particle is marked as "LOST", which I've disabled).
>>
>> Anyone have any additional insight here? At the moment, particles are
>> deleted as soon as they leave the domain, even with the changes I've made.
>>
>> Thanks,
>> - James
>>
>> On Fri, Mar 27, 2015 at 4:58 PM, Anshu Dubey <adubey at lbl.gov> wrote:
>>
>>> If you don't need them to interact with the mesh in anyway I don't see
>>> any conceptual problem with advancing them. You will still have to make
>>> sure that they are not treated the same as particles within domain
>>> in any function.
>>>
>>> Anshu
>>>
>>> On Fri, Mar 27, 2015 at 1:48 PM, James Guillochon <jfg at ucolick.org>
>>> wrote:
>>>
>>>> Hi all, I'm using active particles in my calculation, and I would like
>>>> to continue to evolve the particle trajectories even once the particles
>>>> have left the domain. I see that particles that leave the domain can be
>>>> saved after they leave by enabling a flag, but it appears that their
>>>> evolution at this point is frozen. It looks like a few relatively simple
>>>> changes in Particles_advance may be able to continue their evolution, but I
>>>> wasn't sure if evolving these particles would cause issues.
>>>>
>>>> Has anyone tried to do something like this before?
>>>>
>>>> Cheers,
>>>> - James
>>>>
>>>> --
>>>> James Guillochon
>>>> Einstein Fellow at the Harvard-Smithsonian CfA
>>>> jguillochon at cfa.harvard.edu
>>>>
>>>
>>>
>>>
>>> --
>>> Anshu Dubey <adubey at lbl.gov>
>>> Mailstop: 50A1148
>>> Building-Room 050A-2154
>>> 510-486-5242
>>>
>>
>>
>>
>> --
>> James Guillochon
>> Einstein Fellow at the Harvard-Smithsonian CfA
>> jguillochon at cfa.harvard.edu
>>
>
>
>
> --
> James Guillochon
> Einstein Fellow at the Harvard-Smithsonian CfA
> jguillochon at cfa.harvard.edu
>
>


-- 
James Guillochon
Einstein Fellow at the Harvard-Smithsonian CfA
jguillochon at cfa.harvard.edu
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