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Hello Ashish,<br>
<br>
You can play around the Line {#} In Surface {#} command for the wake
region.<br>
<br>
Regards,<br>
Pawel<br>
<br>
<div class="moz-cite-prefix">W dniu 2016-07-12 o 21:57, ashish bhole
pisze:<br>
</div>
<blockquote
cite="mid:CAExBfEJsxkUtfCinUa1icyYFqBLKhMC5_VW9HuJLTJ5bXbC86Q@mail.gmail.com"
type="cite">
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<div>
<div>
<div>Hello Guillaume,<br>
<br>
</div>
Thank you so much for you help.<br>
<br>
</div>
Can I extend the same boundary layer into wake region? I tried
doing the same by drawing a line from trailing edge to
farfield and creating boundary layer around it. But I have not
succeeded yet.<br>
<br>
</div>
<div>-- With Regards<br>
</div>
<div>Ashish<br>
</div>
<div>
<div>
<div>
<div> <br>
<br>
<br>
</div>
</div>
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<div class="gmail_extra"><br>
<div class="gmail_quote">On Tue, Jul 12, 2016 at 12:36 PM,
DILASSER Guillaume <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:Guillaume.DILASSER@cea.fr" target="_blank">Guillaume.DILASSER@cea.fr</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div link="blue" vlink="purple" lang="FR">
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"
lang="EN-US">Hello Ashish,</span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"
lang="EN-US"> </span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"
lang="EN-US">You can add to the BoundaryLayer
definition the property “Field[1].FanNodesList =
{1,n} ;” to get rid of the weird behavior of the
mesh around the tips of the foil. Somehow, the 2D
blossom recombination algorithm does not like when
you do that so replace it with the standard one
using “Mesh.RecombinationAlgorithm = 0 ;”. Both
modifications are done in the enclosed file.
Finally, you may want to increase the mesh density
at the front of the foil to better match the
geometry there.</span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"
lang="EN-US"> </span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"
lang="EN-US">Sincerely Yours,</span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Tahoma",sans-serif;color:#000099">Guillaume
DILASSER</span><span
style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:#000099"></span></p>
<p class="MsoNormal"><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#000099">Doctorant
SACM / LEAS</span></p>
<p class="MsoNormal"><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#000099">CEA
- Centre de Saclay - Bât.123 - PC 319c</span><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#000099"></span></p>
<p class="MsoNormal"><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#000099">91191
Gif sur Yvette Cedex - France -</span><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#000099"></span></p>
<p class="MsoNormal"><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#000099"> </span></p>
<p class="MsoNormal"><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#000099"><a
moz-do-not-send="true"
href="mailto:guillaume.dilasser@cea.fr"
target="_blank">guillaume.dilasser@cea.fr</a></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"
lang="EN-US"> </span></p>
<p class="MsoNormal"><b><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif"
lang="EN-US">De :</span></b><span
style="font-size:11.0pt;font-family:"Calibri",sans-serif"
lang="EN-US"> gmsh [mailto:<a moz-do-not-send="true"
href="mailto:gmsh-bounces@ace20.montefiore.ulg.ac.be" target="_blank">gmsh-bounces@ace20.montefiore.ulg.ac.be</a>]
<b>De la part de</b> ashish bhole<br>
<b>Envoyé :</b> lundi 11 juillet 2016 19:02<br>
<b>À :</b> <a moz-do-not-send="true"
href="mailto:gmsh@onelab.info" target="_blank">gmsh@onelab.info</a><br>
<b>Objet :</b> [Gmsh] Problem with Boundary Layer
around 2D airfoil with sharp trailing edge</span></p>
<div>
<div class="h5">
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<div>
<div>
<div>
<div>
<div>
<div>
<p class="MsoNormal"
style="margin-bottom:12.0pt"><span
lang="EN-US">Hello All,</span></p>
</div>
<p class="MsoNormal"
style="margin-bottom:12.0pt"><span
lang="EN-US">I am new at using gmsh. I
want to generate a mesh (unstructured)
around 2D airfoil with sharp trailing
edge. When I use Boundary Layer field
in gmsh, it generates boundary layer
but with undesirable intersections. I
have attached my .geo file here.
Currently, I have commented Boundary
Layer field lines in the script.
</span></p>
</div>
<p class="MsoNormal"><span lang="EN-US">Please
share idea how can I make it work
correctly.</span></p>
</div>
<p class="MsoNormal"
style="margin-bottom:12.0pt"><span
lang="EN-US">Thank you.<br>
<br>
------------------------------------<br>
Mesh.RecombineAll = 1;<br>
<br>
Li = 50.0; // distance of inflow boundary
from origin<br>
Lo = 50.0; // distance of outflow boundary
from origin<br>
<br>
n = 50; // points on upper/lower surface
of airfoil used to define airfoil<br>
// These points may not appear in
the mesh.<br>
<br>
lc1 = 10.0;<br>
lc2 = 0.05;<br>
<br>
m = 2*n - 2; // total number of points on
airfoil without repetition<br>
// LE and TE points are
common to upper/lower surface<br>
<br>
nle = n; // point number of LE = no. of
points on upper surface<br>
// Point(1) is trailing edge<br>
<br>
// NACA0012 profile<br>
// formula taken from </span><a
moz-do-not-send="true"
href="http://turbmodels.larc.nasa.gov/naca0012_val.html"
target="_blank"><span lang="EN-US">http://turbmodels.larc.nasa.gov/naca0012_val.html</span></a><span
lang="EN-US"><br>
Macro NACA0012<br>
x2 = x * x;<br>
x3 = x * x2;<br>
x4 = x * x3;<br>
y = 0.594689181*(0.298222773*Sqrt(x) <br>
- 0.127125232*x - 0.357907906*x2 +
0.291984971*x3 - 0.105174606*x4);<br>
Return<br>
<br>
// put points on upper surface of airfoil<br>
For i In {1:n}<br>
theta = Pi * (i-1) / (n-1);<br>
x = 0.5 * (Cos(theta) + 1.0);<br>
Call NACA0012;<br>
Point(i) = {x, y, 0.0, lc2};<br>
xx[i] = x;<br>
yy[i] = y;<br>
EndFor<br>
<br>
// put points on lower surface of airfoil,
use upper surface points and reflect<br>
For i In {n+1:m}<br>
Point(i) = {xx[2*n-i], -yy[2*n-i], 0.0,
lc2};<br>
EndFor<br>
<br>
Spline(1) = {1:n};<br>
Spline(2) = {n:m, 1};<br>
<br>
Point(1000) = {1.0, Li, 0.0,lc1};<br>
Point(1001) = {0.0, Li, 0.0,lc1};<br>
Point(1002) = {-Li, 0.0, 0.0,lc1};<br>
Point(1003) = {0.0, -Li, 0.0,lc1};<br>
Point(1004) = {1.0, -Li, 0.0,lc1};<br>
<br>
Point(1005) = {Lo, 0.0, 0.0,lc1};<br>
Point(1006) = {Lo, Li, 0.0,lc1};<br>
Point(1007) = {Lo, -Li, 0.0,lc1};<br>
<br>
Line(5) = {1000, 1001};<br>
Circle(6) = {1001, nle, 1002};<br>
Circle(7) = {1002, nle, 1003};<br>
Line(8) = {1003, 1004};<br>
Line(13) = {1005, 1006};<br>
Line(14) = {1005, 1007};<br>
Line(15) = {1006, 1000};<br>
Line(16) = {1007, 1004};<br>
<br>
Line Loop(1) = {1,2};<br>
Line Loop(2) = {5,6,7,8,-16,-14,13,15};<br>
<br>
Plane Surface(201) = {2,1};<br>
<br>
/*<br>
//Define Boundary Layer<br>
Field[1] = BoundaryLayer;<br>
Field[1].EdgesList = {1,2};<br>
Field[1].NodesList = {1,m};<br>
Field[1].hfar = 0.05;<br>
Field[1].hwall_n = 0.009;<br>
Field[1].thickness = 0.2;<br>
Field[1].ratio = 1.1;<br>
Field[1].AnisoMax = 10;<br>
Field[1].Quads = 1;<br>
Field[1].IntersectMetrics = 0;<br>
BoundaryLayer Field = 1;<br>
*/<br>
------------------------------------<br>
<br>
</span></p>
</div>
<p class="MsoNormal">-- With Reagrds</p>
</div>
<p class="MsoNormal">Ashish Bhole </p>
</div>
</div>
</div>
</div>
</div>
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