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<p>Dear NN,</p>
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</p>
<p>If your flow is turbulent the answer is definitely Yes (they will be different) because of the standard sensitivity to initial condition concerns.</p>
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<p>Despite this, both schemes are O(dt^k) accurate, meaning that as dt-->0, the error goes to _zero_ as dt^k, where k=Torder is the prescribed temporal order. Since the error goes to zero, both will deliver the same answer provided that the physical solution
is stable and has an attractor. [Understanding when such conditions prevail is often a challenge.]</p>
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<p>Paul</p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Nek5000-users <nek5000-users-bounces@lists.mcs.anl.gov> on behalf of nek5000-users@lists.mcs.anl.gov <nek5000-users@lists.mcs.anl.gov><br>
<b>Sent:</b> Monday, November 6, 2017 6:13:11 AM<br>
<b>To:</b> nek5000-users@lists.mcs.anl.gov<br>
<b>Subject:</b> [Nek5000-users] IFCHAR option in rea file</font>
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<div class="PlainText">Hello,<br>
<br>
I have been using IFCHAR = TRUE in my simulations. The CFL number is <br>
around<br>
1.2 and the computations appear to go on nicely. I would like to know<br>
if the flow field computed using IFCHAR=TRUE option is different than the<br>
one obtained with IFCHAR=FALSE (albeit with smaller dt)? If yes, can the <br>
difference<br>
be significant?<br>
<br>
Many thanks,<br>
NN<br>
<br>
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