<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"> <META content="MSHTML 6.00.2900.3059" name=GENERATOR></HEAD> <BODY> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>Dear Julio,</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>in addition to Achim´s mail following informations:</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>the default value of underelaxation is 0.25, which you can find in the source file /esrumfs/mfmach.F.</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>But be aware that for activating underelaxation (for surpressing oscillations) you must</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>de-comment the relaxation loop in the source-file mfmach.F first !!!</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>In the standard source code the relaxation-loop is NOT valid (commented resp. deactivated) .....</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>Above the loop you will find a fortran line with the relax-factor of 0.25; you can change this</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>value in the source code.</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>But also be aware of the variable ITRPAS, which does - in the current version 11.2 (11.3 not yet investigated) -</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>NOT work correctly. The value of ITRPAS always remains at the integer value of 0 and thus the if-condition</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>never is fulfilled. In version 11.2 you also have to change this source line with the if-statement for activating underrelaxation ....</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>Good luck with underelaxation (which´is VERY important for surpressing oscillations between thermal and air flow domain) !</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>regards,</FONT></SPAN></DIV> <DIV><SPAN class=224494310-18042007><FONT face=Arial color=#0000ff size=2>Gunter</FONT></SPAN></DIV> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid"> <DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma size=2>-----Original Message-----<BR><B>From:</B> esp-r-bounces@lists.strath.ac.uk [mailto:esp-r-bounces@lists.strath.ac.uk]<B>On Behalf Of </B>giulio benincasa<BR><B>Sent:</B> Wednesday, April 18, 2007 11:57 AM<BR><B>To:</B> esp-r@lists.strath.ac.uk<BR><B>Subject:</B> [esp-r] Time step control relaxation<BR><BR></FONT></DIV>Dear all, <BR><BR>I have read that is possible change relaxation parameter <BR><BR>in source code to calm oscillations results  arrange to  (in the air-flow network) similar temperature nodes and <BR><BR>flow-connections that have very little pressure drops across them. <BR><BR>There is anybody that know tje soutce code file where  make  modify  ??<BR><BR>Best regards <BR><BR>Thank you in advance <BR><BR>Giulio Benincasa<BR><BR><BR></BLOCKQUOTE></BODY></HTML>