[Nek5000-users] problem with 2d axisymmetric numerical simulation
nek5000-users at lists.mcs.anl.gov
nek5000-users at lists.mcs.anl.gov
Thu Jan 5 14:09:08 CST 2017
Hi SL,
Attached is a tar file with an axisymmetric expansion case and a couple of README files.
Please give this a try -- hope this helps you to understand how genbox can do this.
Paul
________________________________________
From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov]
Sent: Tuesday, January 03, 2017 12:04 PM
To: nek5000-users at lists.mcs.anl.gov
Subject: Re: [Nek5000-users] problem with 2d axisymmetric numerical simulation
Hi Paul,
thank you very much, it works!
However, I am trying to re-define the geometry generated by genbox:
#
Box
-12 -4 nelx,nely,nelz for Box)
-2.0 4.0 1.0 x0 x1 ratio
0.0 1.0 0.6 y0 y1 ratio
P ,P ,A ,W , bc's
The idea is to generate 3 different squared domains:
-----------
| |
-------- y1
| |----| y2 |
|
------------------------|
x1 x2
So, I have included in usrdat2 subroutine:
do i=1,ntot
if (xm1(i,1,1,1).lt.x1) then
ym1(i,1,1,1)=y1
elseif (xm1(i,1,1,1).ge.x1.and.xm1(i,1,1,1).lt.x2) then
ym2(i,1,1,1)=y2
end if
end do
However, when I run Nek5000 I obtain the following error...
call usrdat2
done :: usrdat2
regenerate geometry data 1
0 ERROR: Vanishing Jacobian near 5th node of element
4.
-2.0182169769993447E-015 0.18749999999999875
0 xyz: -1.20930E+00 5.00000E-01
0 xyz: -7.90701E-01 6.25000E-01
Is there any different way to create these several domains using genbox?
Thank you
SL
El 03-01-2017 18:26, nek5000-users at lists.mcs.anl.gov escribió:
> Hi SL,
>
> Attached is an axisymmetric example that I've just set up.
>
> Several subdomains are also possible, but you must pay attention
> to the "A " bc.
>
> Please let me know if the attached works and gives the right answer.
> It looked ok, but I confess I didn't get out a paper and pencil to
> verify
> that the answer is indeed correct....
>
> Paul
>
> ________________________________________
> From: nek5000-users-bounces at lists.mcs.anl.gov
> [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of
> nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov]
> Sent: Tuesday, January 03, 2017 10:07 AM
> To: nek5000-users at lists.mcs.anl.gov
> Subject: Re: [Nek5000-users] problem with 2d axisymmetric numerical
> simulation
>
> Dear Paul,
>
> thank you very much for your rapid response.
>
> I have used 'A ' BC in the edge 1, however the problem persists... I am
> wondering if the problem could be in how I have defined my geometry:
>
> Is it necessary to define edge 1 as x \in [0,10]? Because I have
> defined
> x \in [-2,8]...
> Is it possible to generate edge 1 as a combination of several
> subdomains? Because I have divided the geometry in 3 subdomains...
>
> Thank you in advance.
> SL
>
> El 03-01-2017 14:38, nek5000-users at lists.mcs.anl.gov escribió:
>> Dear SL,
>>
>> For axisymmetric, if the domain contains the axis, then only points
>> along Edge 1
>> are allowed to be on the axis. That means that the reference domain,
>> shown
>> here in the preprocessor notation,
>>
>> 3
>> +-------------+
>> | |
>> 4 | | 2
>> | |
>> +-------------+
>> 1
>>
>> must have Edge 1 on the axis and that the BC for edge 1 must be "A "
>>
>> If you generate your domain with genbox, this is easily accomplished
>> with something like
>> the following in a case.box file:
>>
>> your.rea
>> 2 spatial dimension
>> -1 number of fields
>> #
>> # comments
>> #
>> #
>> #========================================================
>> #
>> Box
>> -6 -4 nelx,nely,nelz for Box)
>> 0 6 1.0 x0 x1 ratio
>> 0 1 0.7 y0 y1 ratio
>> P ,P ,A ,f , bc's
>>
>>
>> hth,
>>
>> Paul
>>
>>
>> ________________________________________
>> From: nek5000-users-bounces at lists.mcs.anl.gov
>> [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of
>> nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov]
>> Sent: Tuesday, January 03, 2017 7:12 AM
>> To: Nek5000 Users
>> Subject: [Nek5000-users] problem with 2d axisymmetric numerical
>> simulation
>>
>> Hi Neks,
>>
>> I am trying to simulate a circular pipe. To start with, I am trying to
>> perform the 2d axisymmetric simulation. I have generated my mesh using
>> gmsh, and then converted it to nek5000 format. The 2d numerical
>> simulation is properly working, however, I am finding some troubles
>> with
>> the axisymmetric simulation.
>>
>> When I try to run my simulation, I find the following message, and the
>> code stop running:
>> read .rea file
>> nelgt/nelgv/lelt: 1192 1192 200
>> lx1 /lx2 /lx3 : 6 4 4
>>
>> mapping elements to processors
>> 0 149 149 1192 1192 NELV
>> 1 149 149 1192 1192 NELV
>> 2 149 149 1192 1192 NELV
>> 3 149 149 1192 1192 NELV
>> 4 149 149 1192 1192 NELV
>> 5 149 149 1192 1192 NELV
>> 6 149 149 1192 1192 NELV
>> 7 149 149 1192 1192 NELV
>> RANK 0 IEG 474 475 476 477 478 479
>> 480
>> 481
>> 482 483 484 485 486 487
>> 488
>> 489
>> 490 492 493 494 495 496
>> 497
>> 498
>> 499 500 501 502 503 504
>> 505
>> 506
>> 507 508 510 511 512 513
>> 514
>> 515
>> 516 517 518 519 520 521
>> 522
>> 523
>> 524 525 526 528 529 530
>> 531
>> 532
>> 533 534 535 536 537 538
>> 539
>> 540
>> 541 542 543 544 546 547
>> 548
>> 549
>> 550 551 552 553 554 555
>> 556
>> 557
>> 558 559 560 561 562 565
>> 566
>> 567
>> 568 569 570 571 572 573
>> 574
>> 575
>> 576 577 578 579 580 583
>> 584
>> 585
>> 586 587 588 589 590 591
>> 592
>> 593
>> 594 595 596 597 598 602
>> 603
>> 604
>> 605 606 607 608 609 610
>> 611
>> 612
>> 620 621 622 623 624 625
>> 626
>> 627
>> 628 639 640 641 642 643
>> 644
>> 657
>> 658 659 660 676 677
>> element load imbalance: 0 149 149
>> done :: mapping elements to processors
>>
>> 0 objects found
>> done :: read .rea file 0.25710E-01 sec
>>
>> setup mesh topology
>> Element face on the axis of symmetry must be FACE 1
>> Element 6 face 2 is on the axis.
>> Element face on the axis of symmetry must be FACE 1
>> Element 1 face 2 is on the axis.
>> Element face on the axis of symmetry must be FACE 1
>> Element 1 face 3 is on the axis.
>> Right-handed check complete for 1192 elements. OK.
>> Element face on the axis of symmetry must be FACE 1
>> Element 2 face 2 is on the axis.
>> Element face on the axis of symmetry must be FACE 1
>> Element 1 face 2 is on the axis.
>>
>>
>>
>> Following this post:
>> http://lists.mcs.anl.gov/pipermail/nek5000-users/2012-August/001906.html
>>
>> 1) I have set
>> T IFAXIS
>> T IFAZIV
>> 2) I have set 'A ' BC in the region of y=0.
>> 3) I have copied the FLUID BC to the region of THERMAL BOUNDARY
>> CONDITIONS, modifying
>> W, v and O by t
>> 4) In the .usr file I have defined:
>> c-----------------------------------------------------------------------
>>> subroutine userf (ix,iy,iz,eg)
>>> include 'SIZE'
>>> include 'TOTAL'
>>> include 'NEKUSE'
>>> integer e,f,eg
>>> if(y.gt.0) ffy = temp*temp/y
>>> return
>>> end
>>> c-----------------------------------------------------------------------
>>> subroutine userq (ix,iy,iz,eg)
>>> include 'SIZE'
>>> include 'TOTAL'
>>> include 'NEKUSE'
>>> integer e,f,eg
>>> if(y.gt.0) then
>>> visc = param(2)
>>> qvol = -uy*temp/y
>>> endif
>>> return
>>> end
>>> c-----------------------------------------------------------------------
>>> subroutine useric (ix,iy,iz,ieg)
>>> include 'SIZE'
>>> include 'TOTAL'
>>> include 'NEKUSE'
>>> temp = y
>>> return
>>> end
>>> c-----------------------------------------------------------------------
>>>
>>
>> Please, could you give me a piece of advise with this numerical
>> simulation?
>>
>> Thank you very much in advance.
>>
>> SL
>>
>> _______________________________________________
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>> Nek5000-users at lists.mcs.anl.gov
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>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>
>
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