Re: [mesa-users] exploring vibrations in mesa/star models

SourceForge Headquarters 225 Broadway Suite 1600 San Diego, CA 92101 +1 (858) 422-6466

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
  <title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
If I'm not mistaken, mesa uses an implicit time step method even when
you have velocity turned on. Such methods are inherently strongly
damped. If you want to realistically model vibrations, you need a time
step method specially formulated to avoid dissipation (such as some
variation of centered difference.)<br>
<br>
--Kent G. Budge<br>
CCS-2, LANL<br>
<br>
Bill Paxton wrote:
<blockquote
 cite="mid:33D...@ki..."
 type="cite">
  <pre wrap="">Hi,

On Jan 1, 2012, at 8:49 PM, <a class="moz-txt-link-abbreviated" href="mailto:jin...@ca...">jin...@ca...</a> wrote:

  </pre>
  <blockquote type="cite">
    <pre wrap="">we start with a perturbed initial model. Physically
the star should keep vibrating for a thermal (kh_timescale) time scale,
but mesa damped the vibration in about 1 vibration period
    </pre>
  </blockquote>
  <pre wrap=""><!---->
Does anyone have suggestions for Jing?
All I can think of is to set max_years_for_timestep
to make sure the timestep is limited
to be much smaller than the period of vibration.
But I don't have any direct experience with this
sort of thing, so perhaps someone else has
better ideas.

-Bill


------------------------------------------------------------------------------
Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex
infrastructure or vast IT resources to deliver seamless, secure access to
virtual desktops. With this all-in-one solution, easily deploy virtual 
desktops for less than the cost of PCs and save 60% on VDI infrastructure 
costs. Try it free! <a class="moz-txt-link-freetext" href="http://p.sf.net/sfu/Citrix-VDIinabox">http://p.sf.net/sfu/Citrix-VDIinabox</a>
_______________________________________________
mesa-users mailing list
<a class="moz-txt-link-abbreviated" href="mailto:mes...@li...">mes...@li...</a>
<a class="moz-txt-link-freetext" href="https://lists.sourceforge.net/lists/listinfo/mesa-users">https://lists.sourceforge.net/lists/listinfo/mesa-users</a>
  </pre>
</blockquote>
<br>
</body>
</html>