[Nek5000-users] Nek5000-users Digest, Vol 94, Issue 1

[nek5000-users at lists.mcs.anl.gov]

Hi Sandeep,
Is your self-defined udiiff a non-dimensional one? If not, maybe you can try
to set dimensionless properties in uservp subroutine, then the non-positive
error may disappear.

Cheers,
Bolun

----------------------------------------------------------------
Bolun Xu
University of Science and Technology of China
Department of Modern Mechanics
Hefei, Anhui, China

 

-----邮件原件-----
发件人: nek5000-users-bounces at lists.mcs.anl.gov
[mailto:nek5000-users-bounces at lists.mcs.anl.gov] 代表
nek5000-users-request at lists.mcs.anl.gov
发送时间: 2016年12月2日 4:18
收件人: nek5000-users at lists.mcs.anl.gov
主题: Nek5000-users Digest, Vol 94, Issue 1

Send Nek5000-users mailing list submissions to
	nek5000-users at lists.mcs.anl.gov

To subscribe or unsubscribe via the World Wide Web, visit
	https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
or, via email, send a message with subject or body 'help' to
	nek5000-users-request at lists.mcs.anl.gov

You can reach the person managing the list at
	nek5000-users-owner at lists.mcs.anl.gov

When replying, please edit your Subject line so it is more specific than
"Re: Contents of Nek5000-users digest..."


Today's Topics:

   1. uservp MHD error (nek5000-users at lists.mcs.anl.gov)


----------------------------------------------------------------------

Message: 1
Date: Thu, 1 Dec 2016 18:31:45 +0100
From: nek5000-users at lists.mcs.anl.gov
To: nek5000-users at lists.mcs.anl.gov
Subject: [Nek5000-users] uservp MHD error
Message-ID:
	<mailman.7023.1480623493.3602.nek5000-users at lists.mcs.anl.gov>
Content-Type: text/plain; charset="utf-8"

Hello All,

I want to run MHD case with different magnetic diffusivities in different
region of the domain.
Can we run MHD run with different magnetic diffusivities?
Assuming that udiff=magnetic diffusivity (eta), in the uservp file I added
the following

      1.0000000E+00     p30 > 0 ==> properties set in uservp()

      subroutine uservp (ix,iy,iz,ieg)
      include 'SIZE'
      include 'TOTAL'
      include 'NEKUSE'

      if (ifield.eq.1) then ! velocity
utrans = param(1)
udiff  = param(2)
      elseif (ifield.eq.ifldmhd) then ! B-field utrans = 1.0
        R1 = sqrt(x*x+y*y);
if(R1 .le. 2.0) then
udiff= param(29)
else
udiff= 1000.0D0*param(29)
endif
 endif

      return
      end

I get an error

 done :: set initial conditions

  ERROR:  Non-positive diffusivity (    0.00    ) specified for field 2,
group 0 element
  ERROR:  Non-positive diffusivity (    0.00    ) specified for field 2,
group 0 element

Attached are the .usr, .rea and the logfile

When I set the p30=0.000 and just utrans=0.0 udiff=0.0 in the uservp, the
simulation is running fine.
Thank you in advance.

Cheers,
Sandeep
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.mcs.anl.gov/pipermail/nek5000-users/attachments/20161201/cdb6d
a49/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: gpf.usr
Type: application/octet-stream
Size: 12369 bytes
Desc: not available
URL:
<http://lists.mcs.anl.gov/pipermail/nek5000-users/attachments/20161201/cdb6d
a49/attachment.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: gpf.rea
Type: application/octet-stream
Size: 14433846 bytes
Desc: not available
URL:
<http://lists.mcs.anl.gov/pipermail/nek5000-users/attachments/20161201/cdb6d
a49/attachment-0001.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: gpf.log.16
Type: application/octet-stream
Size: 18825 bytes
Desc: not available
URL:
<http://lists.mcs.anl.gov/pipermail/nek5000-users/attachments/20161201/cdb6d
a49/attachment-0002.obj>

------------------------------

_______________________________________________
Nek5000-users mailing list
Nek5000-users at lists.mcs.anl.gov
https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users


End of Nek5000-users Digest, Vol 94, Issue 1
********************************************