<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/xhtml; charset=utf-8">
</head>
<body>
<div style="font-family:sans-serif"><div style="white-space:normal">
<p dir="auto">On 15 Aug 2017, at 9:29, Saeid Esmaeilpour wrote:</p>
<p dir="auto"></p></div>
<div style="white-space:normal"><blockquote style="border-left:2px solid #5855D5; color:#5855D5; margin:0 0 5px; padding-left:5px"><p dir="auto">Jody,<br>
my model is about The simulation of currents Circulation from surface to<br>
depth in indian Ocean, and I selected nonHydrostatic=.TRUE., cause I<br>
think the model resolve the Nonlinear terms with nonHydrastatic=True (am I<br>
wrong ?). If I select nonHydrastatic=True, in this case how much should I<br>
set for cg3MaxIters? and If select nonHydrastatic=False, how much for that?<br>
basically for the simulation of currents Circulation and at 2-degree I have<br>
to take non Hydraustatic=false?</p>
</blockquote></div>
<div style="white-space:normal">
<p dir="auto"><code>nonHydrostatic=.True.</code> solves the non-hydrostatic equation for dw/dt, which essentially means the pressure needs to be determined globally from a Poisson equation, and hence the 3-D solver. <code>.False.</code> means that pressure is solved using the hydrostatic approximation (if you don’t know what this is, Google plus a basic GFD course would help).</p>
<p dir="auto">This really has nothing to do with non-linearity until you start resolving scales where the hydrostatic approximation breaks down (basically dw/dt is no longer << rho’g / rho_0). </p>
<p dir="auto">You really only need non-hydrostatic approximation for fine-scale runs looking at internal waves, dense overflows, convection, or other turbulent phenomena. None of which will show up at 2-degree resolution.</p>
<p dir="auto">Cheers, Jody</p>
<p dir="auto"></p></div>
<div style="white-space:normal"><blockquote style="border-left:2px solid #5855D5; color:#5855D5; margin:0 0 5px; padding-left:5px"><p dir="auto">Thanks again,<br>
Saeid<br>
<br>
On Tue, Aug 15, 2017 at 11:59 AM, Jody Klymak <jklymak@uvic.ca> wrote:<br>
</p>
<blockquote style="border-left:2px solid #5855D5; color:#00AFCC; margin:0 0 5px; padding-left:5px; border-left-color:#00AFCC"><p dir="auto">Hi Saied,<br>
<br>
cg3dMaxIters is only used if nonHydrostatic=.True.. You aren’t resolving<br>
any non-hydrostatic physics at 2-degree resolution, so I would suggest<br>
setting nonHydrostatic=.False. Your model runs will be *much* faster.<br>
<br>
Cheers, Jody<br>
<br>
On 15 Aug 2017, at 8:43, Saeid Esmaeilpour wrote:<br>
<br>
Hi Dear users,<br>
could someone please explain to me what are the following PARM02?<br>
when I increase cg3dMaxIters from 50 to 400 (e.g,. cg3dMaxIters=400) the<br>
run speed becomes very slowly. how can I select this value? what's the<br>
criteria for selecting this number? My domain is 510*210 with 20layer and<br>
also my resolution is 2 degree (3704m).<br>
<br>
# Elliptic solver parameters<br>
&PARM02<br>
cg2dMaxIters=1000,<br>
cg2dTargetResidual=1.E-13,<br>
cg3dMaxIters=400,<br>
cg3dTargetResidual=1.E-13,<br>
<br>
Thanks for any help,<br>
Saeid<br>
_______________________________________________<br>
MITgcm-support mailing list<br>
MITgcm-support@mitgcm.org<br>
<a href="http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support">http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support</a><br>
<br>
<br>
_______________________________________________<br>
MITgcm-support mailing list<br>
MITgcm-support@mitgcm.org<br>
<a href="http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support">http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support</a><br>
<br>
</p>
</blockquote></blockquote><br><p dir="auto">_______________________________________________<br>
MITgcm-support mailing list<br>
MITgcm-support@mitgcm.org<br>
<a href="http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support">http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support</a></p>
</div>
<div style="white-space:normal">
</div>
</div>
</body>
</html>