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September 18, 2012, 08:49 |
Parabolic Profile of velocity
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#1 |
New Member
Roberto
Join Date: Oct 2011
Location: Italy
Posts: 17
Rep Power: 15 |
How can I introduce a parabolic profile of velocity at the entrance of a straight tube?
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September 18, 2012, 09:44 |
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#2 |
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
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Greetings Roberto,
Since you're question is so generic, here's a generic answer: http://www.google.com/imghp?q=parabolic+profile But seriously, what's the context? Is it:
Bruno PPS: I've moved this thread to the sub-forum dedicated to FLUENT, given the response on the next post
__________________
Last edited by wyldckat; September 19, 2012 at 17:54. Reason: see "PPS" |
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September 19, 2012, 07:27 |
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#3 |
New Member
Roberto
Join Date: Oct 2011
Location: Italy
Posts: 17
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Bruno, you've got a good sense of humor . Besides that I'm talking about Fluent 14.0. I need a boundary condition that allows me to introduce a completely developped parabolic profile of velocity of a fluid entering a straight tube (3D). I can either create a very long tube, or create this profile in some way, but I don't know how.
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September 20, 2012, 08:02 |
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#4 |
New Member
rayolau
Join Date: Aug 2012
Posts: 23
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Hi, I am working in similar 3D case. At the moment, my macro is this:
____________________________________ #include "udf.h" #define S 0.0016 DEFINE_PROFILE(inlet_x_velocity, thread, index) { real x [ND,ND]; real y; real z; face_t,f; begin_f_loop(f,thread) { F_CENTROID(x,f,thread) y=x[1] z=x[2] if (y>=S) F_PROFILE(f,thread,index)=0.55*double log (double (y/0.0016)) } end_f_loop(f,thread) } _________________________________ But on compiling my UDF I get the error. Any ideas will be appreciated Thanks! |
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September 20, 2012, 11:00 |
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#5 |
Senior Member
Philipp
Join Date: Jun 2011
Location: Germany
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October 1, 2012, 08:03 |
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#6 |
New Member
Roberto
Join Date: Oct 2011
Location: Italy
Posts: 17
Rep Power: 15 |
I'm trying with this one but it tells me Divergence detected in AMG solver
#include "udf.h" #define YMIN 1.2 #define YMAX 1.55 #define UMEAN -0.04150349 #define B 1./7. #define DELOVRH 0.5 DEFINE_PROFILE(x_velocity,t,i) { real y, del, h, x[ND_ND], ufree; /* variable declarations */ face_t f; h = YMAX - YMIN; del = DELOVRH*h; ufree = UMEAN*(B+1.); begin_f_loop(f,t) { F_CENTROID(x,f,t); y = x[1]; if (y <= del) F_PROFILE(f,t,i) = ufree*pow(y/del,B); else F_PROFILE(f,t,i) = ufree*pow((h-y)/del,B); } end_f_loop(f,t) } |
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parabolic, profile |
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