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<div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 12pt;">Hi Wei,<br>
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Your Helmholtz tolerance of 1e-16 is too high (p22) -- velocity components start an interation from 5...4.e-2 residuals and converge to 4...2.e-16.<br>
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Once you lower it, make sure the Divergence tolerance (p21) is still an order or 2 magnitude higher.<br>
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Aleks <br>
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<div style="direction: ltr;" id="divRpF786713"><font color="#000000" face="Tahoma" size="2"><b>From:</b> nek5000-users-bounces@lists.mcs.anl.gov [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> Thursday, November 06, 2014 5:21 AM<br>
<b>To:</b> nek5000-users@lists.mcs.anl.gov<br>
<b>Subject:</b> [Nek5000-users] **ERROR**: Failed in HMHOLTZ<br>
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<div class="gmail_extra"><span style="color:rgb(0,0,0); font-family:Helvetica; font-size:12px">Hi Neks</span>
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<div style="color:rgb(0,0,0); font-family:Helvetica; font-size:12px">when I setup a profile 2D flow, there are informations like this, but the simulation is not crash,</div>
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<div style="margin:0px">Step 800, t= 8.0000000E-02, DT= 1.0000000E-04, C= 0.431 9.2444E+03 1.0117E+01</div>
<div style="margin:0px"> Solving for fluid F T T</div>
<div style="margin:0px"> 800 100 **ERROR**: Failed in HMHOLTZ: VELX 3.7727E-16 5.3129E-02 1.0000E-16</div>
<div style="margin:0px"> 800 100 **ERROR**: Failed in HMHOLTZ: VELY 2.4683E-16 3.5181E-02 1.0000E-16</div>
<div style="margin:0px"> 800 U-PRES gmres: 23 5.6827E-15 1.0000E-14 9.6473E-07 9.5640E-01 2.4052E+00</div>
<div style="margin:0px"> 800 8.0000E-02 1.0044E+01 Fluid done</div>
<div style="margin:0px"> 800 8.00000000000E-02 6.70022578679E-01 1.99103625323E-01 4.70918953356E-01 1dragx</div>
<div style="margin:0px"> 800 8.00000000000E-02 4.12612202513E-01 5.10664067531E-01 -9.80518650173E-02 1dragy</div>
<div style="margin:0px"> dump history points</div>
<div style="margin:0px"> done :: dump history points</div>
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<div>The CFL number is below than 0.5 already, the polynomial order is 7 in this case. when I choose a lower order p, this information will be disappeared after several iteration steps. I have checked the mesh looks fine, the parameters setting are copied
from “ext_cyl” with a smaller values of p21 to p25, I don’t know what is wrong, should I ignore ?</div>
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<div style="color:rgb(0,0,0); font-family:Helvetica; font-size:12px">thanks,</div>
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<div style="color:rgb(0,0,0); font-family:Helvetica; font-size:12px">Wei</div>
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