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Hi Sean,<br>
<br>
I just tried both of these, and it doesn't seem to make any
noticeable difference. Which solver / slope limiter have you used?<br>
<br>
Thanks,<br>
Rukmani <br>
<br>
<div class="moz-cite-prefix">On 02/18/2016 06:37 AM, Sean Couch
wrote:<br>
</div>
<blockquote
cite="mid:0F27016B-B25C-4259-A51B-54F0EE60720E@flash.uchicago.edu"
type="cite">
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Hi Rukmani,
<div class=""><br class="">
</div>
<div class="">I’ve seen something similar with the field loop
advection test. Have you tried setting E_modification and
E_upwind to .TRUE. in your flash.par?</div>
<div class=""><br class="">
</div>
<div class="">Sean</div>
<div class=""><br class="">
<div class="">
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class="">
Sean M. Couch</div>
<div style="color: rgb(0, 0, 0); letter-spacing: normal;
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0px; word-wrap: break-word; -webkit-nbsp-mode: space;
-webkit-line-break: after-white-space;" class="">Assistant
Professor<br class="">
Department of Physics and Astronomy<br class="">
Department of Computational Mathematics, Science, and
Engineering<br class="">
National Superconducting Cyclotron Laboratory/Facility
for Rare Isotope Beams<br class="">
Michigan State University<br class="">
567 Wilson Rd, 3250 BPS<br class="">
East Lansing, MI 48824<br class="">
(517) 884-5035<br class="">
<div class=""><a moz-do-not-send="true"
href="mailto:couch@pa.msu.edu" class="">couch@pa.msu.edu</a></div>
<div class=""><br class="">
<br class="">
<br class="">
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<blockquote type="cite" class="">
<div class="">On Feb 17, 2016, at 9:22 PM, Rukmani
Vijayaraghavan <<a moz-do-not-send="true"
href="mailto:rukmani@virginia.edu" class="">rukmani@virginia.edu</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<div class="">Hi everyone,<br class="">
<br class="">
I've come across an error when updating fluid variables
at the inflow edge of a wind tunnel simulation. I'm
running a simulation of a galaxy (with active dark
matter particles, gas, and passive particles) in a box,
whose fluid is initialized to be identical to the
incoming wind (with vx, vy, vz = 600 km/s, 0, 0). There
is a small error (on the order of 1%) when updating grid
cells near the inflow boundary (with both USM and PPM
solvers), and this error is spatially correlated with
block boundaries. While this error itself is tolerable
as far as the density and pressure go, this has bad
consequences for the magnetic field which grows as the
wind propagates through the box (see attached figure,
xl_boundary). This figure shows slices of Bx at two
timesteps (annotated with block boundaries and magnetic
field vectors). The dynamic range of Bx in this image
has been reduced to highlight these discontinuities. At
the timesteps shown in the attached image, the
fluctuations in Bx are ~1%, but grow with time up to
order unity. I've tried a variety of Riemann solvers
(HLLC, HLLD, Roe, Hybrid), slope limiters (mc, minmod,
etc.), interpolation orders, prolongation methods,
turning on and off specific USM switches, but nothing
seems to solve this issue so far. Has anybody else dealt
with and/or successfully solved this issue?<br class="">
<br class="">
Thanks,<br class="">
Rukmani<br class="">
<br class="">
-- <br class="">
Rukmani Vijayaraghavan<br class="">
NSF Astronomy & Astrophysics Postdoctoral Fellow<br
class="">
University of Virginia<br class="">
<a moz-do-not-send="true"
href="mailto:rukmani@virginia.edu" class="">rukmani@virginia.edu</a><br
class="">
<br class="">
<span
id="cid:2C90733C-EBF6-4D68-BAD5-D1202CB9077B@hsd1.mi.comcast.net."><magxslc_discontinuity.png></span></div>
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<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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