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Hello Gregory<br>
<br>
If you are using the USM scheme, you also need to enforce the
boundary conditions in the face variables (basically, the
MAG_FACE_VAR in FACEX and FACEY structures). If you did not specify
BCs for the face variables in your implementation, probably the code
is using outflow condition for them, so the advancement of the
magnetic field is not what you expect.<br>
<br>
Best regards<br>
<br>
Gustavo<br>
<br>
<div class="moz-cite-prefix">El 28/08/18 a las 06:27, Boyle, Gregory
escribió:<br>
</div>
<blockquote
cite="mid:880917960.15632704.1535448457770.JavaMail.zimbra@desy.de"
type="cite">
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<div>Hi Ernesto,<br>
</div>
<div><br data-mce-bogus="1">
</div>
<div>Thank you very much for your advice!<br
data-mce-bogus="1">
</div>
<div><br data-mce-bogus="1">
</div>
<div>I would like to enforce a B_theta boundary condition,
which should correspond to KAXIS and MAGZ_VAR as you
suggested. This seems consistent with the output of the
standard NohCylindrical test problem having only MAGZ_VAR
be non-zero.<br data-mce-bogus="1">
</div>
<div><br data-mce-bogus="1">
</div>
<div>I tested putting ivar == MAGX_VAR just in case, to no
avail. I am now starting to suspect that, by using the
unsplit staggered mesh, I perhaps need to enforce a
condition on the cell faces.<br data-mce-bogus="1">
</div>
<div><br data-mce-bogus="1">
</div>
<div>Any other advice or suggestions is much appreciated!<br
data-mce-bogus="1">
</div>
<div><br data-mce-bogus="1">
</div>
<div>Cheers,<br data-mce-bogus="1">
</div>
<div>Greg.</div>
<div><br data-mce-bogus="1">
</div>
<div><br data-mce-bogus="1">
</div>
<hr id="zwchr">
<div><b>From: </b>"Ernesto Zurbriggen"
<a class="moz-txt-link-rfc2396E" href="mailto:ezurbriggen@unc.edu.ar"><ezurbriggen@unc.edu.ar></a><br>
<b>To: </b>"flash-users"
<a class="moz-txt-link-rfc2396E" href="mailto:flash-users@flash.uchicago.edu"><flash-users@flash.uchicago.edu></a><br>
<b>Sent: </b>Friday, 24 August, 2018 16:59:00<br>
<b>Subject: </b>Re: [FLASH-USERS] Magnetic field boundary
condition for NohCylindrical test problem<br>
</div>
<br>
<div>
<div dir="ltr">Hi Greg!
<div>I'm not in the details, but remember that in
cylindrical geometry (IAXIS,JAXIS,KAXIS)=(r,z,theta). </div>
<br>
<div>>>I am using the Unsplit Staggered Mesh MHD
solver, and have included a modified
Grid_bcApplyToRegion.F90 that alters the standard
"reflect" condition on the HIGH face of IAXIS to: <br>
</div>
<div>So, if you would like to modify the BC on the HIGH
face of IAXIS, </div>
<br>
<div>>> if(ivar == MAGZ_VAR)
regionData(k-i,1:je,1:ke,ivar)= 1.0 <br>
</div>
<div>maybe you should put ivar == MAGX_VAR instead. </div>
<br>
<div>Best!</div>
<br>
<div>Ernesto </div>
<br class="gmail-Apple-interchange-newline">
</div>
<br>
<div class="gmail_quote">
<div dir="ltr">El vie., 24 ago. 2018 a las 5:48, Boyle,
Gregory (<<a moz-do-not-send="true"
href="mailto:gregory.boyle@desy.de" target="_blank">gregory.boyle@desy.de</a>>)
escribió:<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Dear
FLASH community,<br>
<br>
I am attempting to modify the the 2D NohCylindrical
test problem (32.2.4) to include a permanent
B_{\theta} condition at rightmost r boundary. This is
a first step towards including the effect of a
longitudinal current.<br>
<br>
I am using the Unsplit Staggered Mesh MHD solver, and
have included a modified Grid_bcApplyToRegion.F90 that
alters the standard "reflect" condition on the HIGH
face of IAXIS to:<br>
<br>
k = 2*guard+1<br>
if(isFace)k=k+1<br>
do i = 1,guard<br>
regionData(k-i,1:je,1:ke,ivar)=
regionData(i,1:je,1:ke,ivar)*sign<br>
if(ivar == MAGZ_VAR)
regionData(k-i,1:je,1:ke,ivar)= 1.0<br>
end do<br>
<br>
However, when I look at the output it seems the
condition of setting MAGZ_VAR to 1.0 is being ignored.<br>
<br>
Any suggestions would be greatly appreciated!<br>
<br>
Cheers,<br>
Greg.<br>
</blockquote>
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<div dir="ltr"><span
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Ernesto Zurbriggen</span></i></span>
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