<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
</head>
<body bgcolor="#ffffff" text="#000000">
Hi Neks,<br>
<br>
I am running a linear simulation with fixed dt, p93, 94, 95 > 0,
filtering and dealiasing.<br>
However, it seems velocity projection is not affecting number of
Helmholtz iterations which is fixed after a while.<br>
<br>
I tested for p94=0 and p94>0 and practically got the same number of
iterations (and even a slight increase in time for time step when
p95>0).<br>
However in case of p95=0 and p95>0 I can see the improvement
clearly. So, pressure projection is working fine.<br>
I need tight tolerances, div=1.e-10, hmh=1.e-11, and reducing Hmholtz
iterations can help a lot.<br>
<br>
Would you please clarify the situation on velocity projection in linear
cases?<br>
<br>
Here is a sample time step :<br>
<small>Step1122816, t= 2.8264667E+02, DT= 2.5173018E-04, C= 0.390
6.0349E+04 5.1942E-02<br>
1122816 2.8264667E+02 Perturbation Solve: 1<br>
1122816 Hmholtz VELX: 18 8.3081E-12 1.0343E-01
1.0000E-11<br>
1122816 Hmholtz VELY: 17 8.0312E-12 2.3905E-01
1.0000E-11<br>
***** 11 alpha: 1.5898E-06 2.6447E-09 1.6940E-09 1.5196E-09
3.6127E-10 8.4097E-10 6.6903E-10 -2.2649E-10 -1.5484E-09 -3.4627E-10<br>
****** 11 4.0897E-09 1.8192E-10 2.2480E+01 alph12<br>
1122816 U-PRES gmres: 7 9.4727E-11 1.0000E-10 1.8192E-10
6.8312E-03 1.5541E-02</small><br>
<br>
Best,<br>
Nima<br>
<pre class="moz-signature" cols="72">--
Nima Shahriari
Linné Flow Center, Mechanics KTH
SE-100 44, Stockholm, Sweden
Phone: +46 8 7906876
E-mail: <a class="moz-txt-link-abbreviated" href="mailto:nima@mech.kth.se">nima@mech.kth.se</a></pre>
</body>
</html>