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July 13, 2010, 05:28 |
2 inlets, 2 UDF
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#1 |
New Member
bilalmerei
Join Date: Mar 2010
Posts: 14
Rep Power: 16 |
plz i need an urgent help.
i have to inject oil into water. the problem that water must have a specific profile of velocity so i have to introduce a UDF. and same for the oil. so i don't know how to define 2 UDF and interpret them in each inlet. plz help |
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December 12, 2010, 13:26 |
UDF needed too
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#2 |
New Member
Rajat
Join Date: Dec 2010
Posts: 2
Rep Power: 0 |
I too need udf function for a fully developed velocity profile at inlet in vertical channel . As i have never worked on Fluent i dont know how udf
have to write is it exactly the same code as in FORTRAN or C as i know both well but udf i dont know |
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December 12, 2010, 13:54 |
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#3 |
Senior Member
Real Name :)
Join Date: Jan 2010
Location: United States
Posts: 192
Rep Power: 16 |
UDF's are User Defined Functions
They are typically written in C, but can be written in Fortran. Fluent has a C interpreter built in, so you don't need one unless aspects of the calculation (specific Fluent calls, speed of calculation, etc) require compilation. To impose a fully developed profile at a wall, you must loop over all faces of the wall and set the velocity magnitude (or, perhaps, a vector component) equal to the velocity you obtain from fully developed flow. In the code below, I assume the following: 1) Fully developed laminar flow 2) 2-D flow in the x-direction 3) An inlet face which extends from 0.5 to -0.5 in the y-direction 4) A maximum centerline velocity of 10 Code:
#include "udf.h" DEFINE_PROFILE(inlet_x_velocity, thread, position) { real x[ND_ND]; /* this will hold the position vector */ real y; face_t f; begin_f_loop(f, thread) { F_CENTROID(x,f,thread); y = x[1]; F_PROFILE(f, thread, position) = 10.-10.*(y*y/(0.5*0.5)); } end_f_loop(f, thread) } Go here: http://combust.hit.edu.cn:8080/fluen.../udf/node2.htm for more information on UDFs. ComputerGuy |
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December 13, 2010, 02:04 |
Thanks
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#4 |
New Member
Rajat
Join Date: Dec 2010
Posts: 2
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many thanks to ComputerGuy for you help and code I will try to learn and do whatever is needed furthermore.
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