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<p>Hi Dongwook,</p>
<p>I'm using cfl=0.8. I've used first, second, and third order
reconstruction with no luck. These are 3D simulations, the figures
I attached are 2D slices through the central plane.</p>
<p>Thanks,</p>
<p>Rukmani<br>
</p>
<br>
<div class="moz-cite-prefix">On 10/09/2017 12:07 AM, Dongwook Lee
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CANvkU6EHn7h9GvOgnqGefx1QDkQ3FbQiECC_NoRaDWzKX=uesQ@mail.gmail.com">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<div dir="ltr">Dear Rukmani,
<div><br>
</div>
<div>It looks to me that they may come from numerical
instability, although it could be an issue related to the use
of AMR. What reconstruction scheme and CFL number are you
using? Is this 2D or 3D?</div>
<div><br>
</div>
<div>Best,</div>
<div>Dongwook</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sun, Oct 8, 2017 at 12:59 PM,
Rukmani Vijayaraghavan <span dir="ltr"><<a
href="mailto:rukmani@virginia.edu" target="_blank"
moz-do-not-send="true">rukmani@virginia.edu</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Hi
everyone,<br>
<br>
I get a strange, unphysical feature in the magnetic field
structure with the USM solver, seen in the attached slices
of B_z and the magnetic pressure. These features, as you can
see, track the block boundaries and look like a checkerboard
of varying magnetic field strength (and sign?) in individual
grid cells. I've tried modifying every possible USM solver
switch, including the Riemann solver, order, slope limiter,
prolongation method, steepening, etc. Using Riemann Solver =
HLLC instead of HLLD makes things a little better, since
HLLC is more diffusive, but the feature still eventually
appears. Any advice on solving this or even minimizing its
effects would be helpful!<br>
<br>
Thanks,<br>
<br>
Rukmani<span class="HOEnZb"><font color="#888888"><br>
<br>
-- <br>
Rukmani Vijayaraghavan<br>
NSF Astronomy & Astrophysics Postdoctoral Fellow<br>
University of Virginia<br>
<a href="mailto:rukmani@virginia.edu" target="_blank"
moz-do-not-send="true">rukmani@virginia.edu</a><br>
<br>
</font></span></blockquote>
</div>
<br>
<br clear="all">
<div><br>
</div>
-- <br>
<div class="gmail_signature" data-smartmail="gmail_signature">
<div dir="ltr">
<div style="font-size:12.8px"><font size="2" color="#000000"
face="arial, helvetica, sans-serif"><br>
=========================================</font></div>
<div style="font-size:12.8px"><font size="2" color="#000000"
face="arial, helvetica, sans-serif">Dongwook Lee, Ph.D.,
Assistant Professor</font></div>
<div style="font-size:12.8px"><font size="2" color="#000000"
face="arial, helvetica, sans-serif">Applied Mathematics
and Statistics<br>
</font></div>
<div style="font-size:12.8px"><font size="2" color="#000000"
face="arial, helvetica, sans-serif">University of
California, Santa Cruz</font></div>
<div style="font-size:12.8px"><font size="2" color="#000000"
face="arial, helvetica, sans-serif">Baskin Engineering,
Room 353C</font></div>
<div style="font-size:12.8px"><font size="2" color="#000000"
face="arial, helvetica, sans-serif">1156 High Street,
Santa Cruz, CA 95064</font></div>
<div style="font-size:12.8px"><font size="2" color="#000000"
face="arial, helvetica, sans-serif"><a
href="https://users.soe.ucsc.edu/%7Edongwook/"
target="_blank" moz-do-not-send="true">https://users.soe.ucsc.edu/~dongwook/</a></font></div>
<div><br>
</div>
</div>
</div>
</div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Rukmani Vijayaraghavan
NSF Astronomy & Astrophysics Postdoctoral Fellow
University of Virginia
<a class="moz-txt-link-abbreviated" href="mailto:rukmani@virginia.edu">rukmani@virginia.edu</a></pre>
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