[petsc-users] PETScFE Point Source

[Matthew Knepley]

On Fri, Apr 13, 2018 at 2:37 PM, Stefano Zampini <stefano.zampini at gmail.com>
wrote:

> Il Ven 13 Apr 2018, 21:27 Sanjay Govindjee <s_g at berkeley.edu> ha scritto:
>
>> Wouldn't it make the most sense to do it in a variationally consistent
>> manner
>>
>> rhs_a = int{ N_a delta(x - x_o) }
>>
>> where x_o is the location of the point source?
>>
>
>
> This is what I meant. However, the current callbacks for residual
> evaluation in PetscDS do not allow to do it.
>

And I don't think they should since that is not something that can be done
by quadrature, so the interface is still unclear.
Anyone can code something up ;)

  Matt


> -sanjay
>>
>> On 4/13/18 7:46 PM, Matthew Knepley wrote:
>>
>> On Fri, Apr 13, 2018 at 1:40 PM, Robert Walker <rlwalker at usc.edu> wrote:
>>
>>> Hello,
>>>
>>> Is there an example of application of a point source in one of the
>>> tutorial  PETScFE style examples? Ideally this would be some point on the
>>> interior, and not necessarily on a boundary.
>>>
>>> Thanks, and apologies in advance if this is a stupid question,
>>>
>>
>> No, good question. You would have to decide what that meant in FEM terms.
>> All the internal integrals are done
>> with quadrature. So putting the source at a quadrature point would work,
>> although its a little difficult to know where
>> they will be. You could smooth it out a little, and check coordinates in
>> the forcing function. Last, you could check
>> for a "close enough" quadrature point and put it there. I think making a
>> slightly extended source is usually best.
>>
>>   Thanks,
>>
>>      Matt
>>
>>
>>> Robert
>>>
>>>
>>> Robert L. Walker
>>> MS Petroleum Engineering
>>> Mork Family Department of Chemicals and Materials Sciences
>>> University of Southern California
>>> ----------------------------------------------
>>> Mobile US: +1 (213) - 290 -7101
>>> Mobile EU: +34 62 274 66 40
>>> rlwalker at usc.edu
>>>
>>
>>
>>
>> --
>> What most experimenters take for granted before they begin their
>> experiments is infinitely more interesting than any results to which their
>> experiments lead.
>> -- Norbert Wiener
>>
>> https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/%7Emk51/>
>>
>>
>> --
>> -------------------------------------------------------------------
>> Sanjay Govindjee, PhD, PE
>> Horace, Dorothy, and Katherine Johnson Professor in Engineering
>>
>> 779 Davis Hall
>> University of California
>> Berkeley, CA 94720-1710
>>
>> Voice:  +1 510 642 6060
>> FAX:    +1 510 643 5264s_g at berkeley.eduhttp://faculty.ce.berkeley.edu/sanjay
>> -------------------------------------------------------------------
>>
>> Books:
>>
>> Engineering Mechanics of Deformable Solidshttp://amzn.com/0199651647
>>
>> Engineering Mechanics 3 (Dynamics) 2nd Editionhttp://amzn.com/3642537111
>>
>> Engineering Mechanics 3, Supplementary Problems: Dynamics http://www.amzn.com/B00SOXN8JU
>>
>> NSF NHERI SimCenterhttps://simcenter.designsafe-ci.org/
>> -------------------------------------------------------------------
>>
>>
>>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
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