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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Calibri;mso-fareast-language:EN-US">Hi All,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Calibri;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Calibri;mso-fareast-language:EN-US">Not sure if this is relevant, but if it is related to problems of B field gradient across coarse/fine boundaries then it sounds at least superficially similar
to a problem I had a while ago so I thought I would at least point it out in case there is a connection or possible clues for you (<a href="http://flash.uchicago.edu/pipermail/flash-users/2016-May/001957.html">http://flash.uchicago.edu/pipermail/flash-users/2016-May/001957.html</a>)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Calibri;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Calibri;mso-fareast-language:EN-US">Unfortunately – I never got to the bottom of it and ended up tackling that particular problem with a different code using a stretched grid instead of AMR. I would
however very much like to use FLASH for similar problems so I am watching this thread with great interest…<o:p></o:p></span></p>
<p class="MsoNormal" align="center" style="text-align:center"><span style="font-size:11.0pt;font-family:Calibri;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Calibri;mso-fareast-language:EN-US">Cheers,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Calibri;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Calibri;mso-fareast-language:EN-US">Jonathan<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Calibri;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Calibri;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Calibri;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-family:Calibri;color:black">From: </span>
</b><span style="font-family:Calibri;color:black"><flash-users-bounces@flash.uchicago.edu> on behalf of Dongwook Lee <dongwook@flash.uchicago.edu><br>
<b>Date: </b>Friday, 9 June 2017 at 00:05<br>
<b>To: </b>"Slavin, Jonathan" <jslavin@cfa.harvard.edu><br>
<b>Cc: </b>flash-users <flash-users@flash.uchicago.edu><br>
<b>Subject: </b>Re: [FLASH-USERS] ensuring div B = 0 when adjusting evolution<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hi Jon, <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Do you see large B fluctuations aligned with the fine-coarse block boundaries; and they get larger over time?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Just to add one quick suggestion: what Riemann solver you've been using? If HLLD, can you try to switch to HLLC or HLL and see if the fluctuations still persist?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Cheers,<o:p></o:p></p>
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<p class="MsoNormal">Dongwook<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Fri, May 26, 2017 at 1:38 PM, Slavin, Jonathan <<a href="mailto:jslavin@cfa.harvard.edu" target="_blank">jslavin@cfa.harvard.edu</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:Arial">To answer Sean and Ernesto's questions:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Arial">I am using the USM solver and AMR. I have now determined that div B is still 0 after the second explosion, which is not too surprising since, for this run, I have not changed the magnetic field and include
div B cleaning (killdivb = .true.). So the problem is not with non-zero div B but with the large B fluctuations that are initiated. I noticed that there are small scale fluctuations in the region where the second explosion is initiated before the explosion,
though the field is weak ~ 0.01 muG. The fluctuations after the explosion go from ~ -1000 muG - +1000 muG. I do expect amplification of B field fluctuations at the shock, but not to that extent.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Arial"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Arial">The way I'm initiating the second explosion is (almost) the same way I initiate the first one - I set the pressure of parcels within a given radius to a value such that the sum of the energy in those parcels
is equal to the value I want for the explosion (1.E51 ergs). I set the density to a value so as to have the mass total to 8 solar masses. So all the energy is thermal at first. I'll see about calling the EOS unit, since I haven't done that. Any additional
info on how to do that would be appreciated.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Arial"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Arial">Thanks,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Arial">Jon<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Fri, May 26, 2017 at 1:00 PM, <<a href="mailto:flash-users-request@flash.uchicago.edu" target="_blank">flash-users-request@flash.uchicago.edu</a>> wrote:
<o:p></o:p></p>
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<p class="MsoNormal">---------- Forwarded message ----------<br>
From: ERNESTO ZURBRIGGEN <<a href="mailto:ezurbriggen@unc.edu.ar" target="_blank">ezurbriggen@unc.edu.ar</a>><br>
To: <a href="mailto:flash-users@flash.uchicago.edu" target="_blank">flash-users@flash.uchicago.edu</a><br>
Cc: <br>
Bcc: <br>
Date: Fri, 26 May 2017 10:56:45 -0300<br>
Subject: Re: [FLASH-USERS] ensuring div B = 0 when adjusting evolution<o:p></o:p></p>
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<p class="MsoNormal">Hi Jon! <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-family:Arial">Have you tried to set off a less intense second supernova explosion? Have you observed the same problems in that case? The second explotion might be much too intense. </span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-family:Arial">On the other hand, how do you set the later explotion? I mean, applying the explotion, are you consistently modifying the thermodynamical variables? For example, if you instantaneously modify the density
and the temperature, then you also should call the Eos unit to keep the consistence. I have experimented situations in which just modifying velocities and keeping the thermodynamics unaltered, I also had to call the Eos unit in order to maintain consistence</span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-family:Arial">Some runtime parameter that might help being on are 'shockDetect' and 'shockLowerCFL' (this last one I think is just in realease 4.4). </span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Best!<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">-- <o:p></o:p></p>
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<p class="MsoNormal"><i><span style="font-family:"monospace","serif";color:black">Ernesto Zurbriggen</span></i><i><span style="font-family:"monospace","serif""> </span></i>
<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal"><i><span style="font-family:"monospace","serif";color:#444444">Instituto de Astronomía Teórica y Experimental
</span></i><i><span style="font-family:"monospace","serif";color:#274E13">(IATE)</span></i><i><span style="font-family:"monospace","serif";color:#444444">. </span></i><o:p></o:p></p>
</div>
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<p class="MsoNormal"><i><span style="font-family:"monospace","serif";color:#444444">Observatorio Astronómico de Córdoba
</span></i><i><span style="font-family:"monospace","serif";color:#274E13">(OAC)</span></i><i><span style="font-family:"monospace","serif";color:#444444">, </span></i><i><span style="font-size:9.5pt;font-family:Courier;color:#444444">Universidad Nacional de
Córdoba </span></i><i><span style="font-size:9.5pt;font-family:Courier;color:#274E13">(UNC)</span></i><i><span style="font-size:9.5pt;font-family:Courier;color:#444444">. </span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="font-size:9.5pt;font-family:Courier;color:#444444">Teléfono: +54 0351 4331064-5, interno 222. </span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="font-family:"monospace","serif";color:#444444">Córdoba, Argentina.</span></i><span style="color:#444444"> </span><o:p></o:p></p>
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<p class="MsoNormal"><br>
<br>
---------- Forwarded message ----------<br>
From: "Sean M. Couch" <<a href="mailto:couch@pa.msu.edu" target="_blank">couch@pa.msu.edu</a>><br>
To: "Slavin, Jonathan" <<a href="mailto:jslavin@cfa.harvard.edu" target="_blank">jslavin@cfa.harvard.edu</a>>, flash-users <<a href="mailto:flash-users@flash.uchicago.edu" target="_blank">flash-users@flash.uchicago.edu</a>><br>
Cc: <br>
Bcc: <br>
Date: Fri, 26 May 2017 14:07:22 +0000<br>
Subject: Re: [FLASH-USERS] ensuring div B = 0 when adjusting evolution<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica">Hi Jon,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica">Can you give a little more info? Are you using the USM solver? Are you using AMR? Have you actually checked that divB>0 in the output data? A log file from a representative run would
be useful.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica">In my experience, the USM solver in cylindrical R-Z coordinates with AMR can be….touchy. But it should work and maintain divB=0! (See, e.g., <a href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013ApJ...773..136J&link_type=EJOURNAL" target="_blank">http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013ApJ...773..136J&link_type=EJOURNAL</a>).<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica">Cheers,<o:p></o:p></span></p>
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<div id="m_7673830170894663220m_5462410415856234389bloop_customfont">
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica">Sean<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Helvetica"><br>
----------------------------------------------------------------------------------------------------------<br>
Sean M. Couch<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Helvetica">Assistant Professor<br>
Department of Physics and Astronomy<br>
Department of Computational Mathematics, Science, and Engineering<br>
National Superconducting Cyclotron Laboratory/Facility for Rare Isotope Beams<br>
Michigan State University<br>
567 Wilson Rd, 3250 BPS<br>
East Lansing, MI 48824<br>
<a href="tel:(517)%20884-5035" target="_blank">(517) 884-5035</a> —— <a href="mailto:couch@pa.msu.edu" target="_blank">couch@pa.msu.edu</a> —— <a href="http://www.pa.msu.edu/~couch" target="_blank">www.pa.msu.edu/~couch</a><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Helvetica"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:10.5pt;font-family:Helvetica"><o:p> </o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="m7673830170894663220m5462410415856234389airmailon">On May 25, 2017 at 4:41:45 PM, Slavin, Jonathan (<a href="mailto:jslavin@cfa.harvard.edu" target="_blank">jslavin@cfa.harvard.edu</a>) wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:Arial">Hi all,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Arial"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Arial">I'm running MHD simulations where I set off a second supernova explosion within a pre-existing remnant. I'm using Simulation_adjustEvolution for this. However, I'm running into a problem with the magnetic
field just after initiating the second explosion. I'm getting very large pixel-to-pixel variations in Bx and By at the edge of the new expanding blast wave. I'm thinking that it could be because of non-zero div B in the region in which the explosion is generated.
So my question is, does anyone have a suggestion for div B cleaning at the point that the explosion is started, i.e. within Simulation_adjustEvolution, to prevent the problems I'm having? I don't really expect the B field to be dynamically important inside
the remnant (beta >> 1), so accuracy of the B field is probably not important there. I should add that I'm doing these calculations in 2D cylindrical symmetry (R-Z). Thanks in advance for any help.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Arial"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Arial">Regards,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Arial">Jon<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">_______________________________________________<br>
flash-users mailing list<br>
<a href="mailto:flash-users@flash.uchicago.edu" target="_blank">flash-users@flash.uchicago.edu</a><br>
<a href="http://flash.uchicago.edu/mailman/listinfo/flash-users" target="_blank">http://flash.uchicago.edu/mailman/listinfo/flash-users</a><o:p></o:p></p>
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<p class="MsoNormal">-- <o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">________________________________________________________<br>
Jonathan D. Slavin Harvard-Smithsonian CfA<br>
<a href="mailto:jslavin@cfa.harvard.edu" target="_blank">jslavin@cfa.harvard.edu</a> 60 Garden Street, MS 83<br>
phone: <a href="tel:(617)%20496-7981" target="_blank">(617) 496-7981</a> Cambridge, MA 02138-1516<br>
cell: <a href="tel:(781)%20363-0035" target="_blank">(781) 363-0035</a> USA<br>
________________________________________________________<o:p></o:p></p>
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<br clear="all">
<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">-- <o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Arial;color:black"><br>
=========================================</span><span style="font-size:9.5pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Arial;color:black">Dongwook Lee, Ph.D., Assistant Professor</span><span style="font-size:9.5pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Arial;color:black">Applied Mathematics and Statistics</span><span style="font-size:9.5pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Arial;color:black">University of California, Santa Cruz</span><span style="font-size:9.5pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Arial;color:black">Baskin Engineering, Room 353C</span><span style="font-size:9.5pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Arial;color:black">1156 High Street, Santa Cruz, CA 95064</span><span style="font-size:9.5pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Arial;color:black"><a href="https://users.soe.ucsc.edu/~dongwook/" target="_blank">https://users.soe.ucsc.edu/~dongwook/</a></span><span style="font-size:9.5pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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