CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

How to create non-uniform velocity profile in FLUENT?

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By mmunige

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 12, 1999, 13:43
Default How to create non-uniform velocity profile in FLUENT?
  #1
pankaj
Guest
 
Posts: n/a
hi! I am a new user of FLUENT.I will be grateful if somebody tells me how to apply & create non-uniform velocity profile as boundary conditions.

thanks.
  Reply With Quote

Old   September 12, 1999, 14:12
Default Re: How to create non-uniform velocity profile in FLUENT?
  #2
Allan Zhao
Guest
 
Posts: n/a
Hello, there are a few ways to create non-uniform velocity profile as boundary conditions. If you know the Graphical User Guide, you can go to create boundary panel. There are three velocity components to input (u,v,w). Below each input bar, you will see a defaut "constant" input request. You can change that to piecewise, polynomail or harmonic profiles. After you click each of these choices, next step will be straightforward to you. Good luck. Allan
  Reply With Quote

Old   September 13, 1999, 16:08
Default Re: How to create non-uniform velocity profile in FLUENT?
  #3
Demselles Hollowajiawoak
Guest
 
Posts: n/a
You could write a profile and read it into Fluent example from the menu pick read profile

((profile_vel_inlet 4) (x 0 0 0 0 ) (y 0 0.25 0.5 0.75 ) (x-velocity 0 0.5 0.5 0) )

Note: the 4 represents the total number of points in the profile. When you set the boundary condition and choose the correct profile, fluent interpolates the values so if your grid is unstructured your profile does not have to match the grid locations.

regards Demselles
  Reply With Quote

Old   October 3, 1999, 13:24
Default Re: How to create non-uniform velocity profile in FLUENT?
  #4
Marco Bonizzi
Guest
 
Posts: n/a
Hello,

I'm writing to you from Italy.As FLUENT/UNS user I just can tell you that, in order to use a non-uniform velocity profile, you should do it by a FORTRAN routine. Unfortunately I cannot tell you anything else. Best luck!
  Reply With Quote

Old   October 21, 1999, 06:26
Default Re: How to create non-uniform velocity profile in FLUENT?
  #5
glenn creten
Guest
 
Posts: n/a
Dear Marco,

I have used non-uniform profiles for velocity and other scalars. I think the easiest way to create these profiles in Fluent is as I did:

First write out your profile at the inlet boundary You then obtain a profile file, which contains vectors of x, y, z, and (e.g.) the velocity components You can read these data in a spreadsheet, e.g. Excel, and replace the velocity components by a function of x,y,z. Then save the altered data as text file, and read this back in into Fluent as profile. Finally, you can then use these profiles as boundary conditions for the inlet.

Good luck,

Glenn.

PS. Can you transmit this to the person that posted the original question, since his mail was not on the discussion forum
  Reply With Quote

Old   January 4, 2010, 23:43
Default
  #6
New Member
 
ang
Join Date: Oct 2009
Posts: 1
Rep Power: 0
ang4335495 is on a distinguished road
Hello, I am new Fluent user. From this forum, I have read the case about using Excel to create the wind profile. However, there are some problems that I need help from guests inside this forum. First, I have tried to write the profile file using fluent and what shows in the excel is only X - vector. How can I get Y and Z vectors results? Another problem is that how can I write a new profile based on the excel file? By using calculation such as wind power law to calculate it? Hope one of the guest inside here can reply me soon. Thank you!
ang4335495 is offline   Reply With Quote

Old   March 29, 2012, 06:46
Default Non uniform velocity at inlet of domain
  #7
New Member
 
PARESH GUJARATI
Join Date: Jan 2012
Posts: 4
Rep Power: 14
p07ip705 is on a distinguished road
First you run the problem with constant velocity and then write profile for that constant velocity input. Now change the input velocity as per your requirement and re-read that profile file and solve the problem.
p07ip705 is offline   Reply With Quote

Old   October 24, 2016, 05:52
Question UDF for inlet temperature
  #8
New Member
 
mm
Join Date: May 2016
Posts: 24
Rep Power: 9
mmunige is an unknown quantity at this point
Dear all

I have following UDF for inlet temperature, untill 1300s it takes correct values according to equation, but after 1300s values are higher and not accorrding to equation, like at 1301s it should have value of 405C but in simulation inlet temperature is 621C. I could not find the error in my UDF after lot of try. please check this and guide me
#include"udf.h"

DEFINE_PROFILE(inlet_temperature,thread,position )

{

face_t f;

begin_f_loop(f,thread)

{

real t = RP_Get_Real("flow-time");

if (t <=1300.0 )

{

F_PROFILE(f,thread,position) = 379.13 + 0.0005*t;

}

else if (1300.0 < t && t <= 1500.0 )

{

F_PROFILE(f,thread,position)= -1.04289036878969*pow(10,-10)*pow(t,6.0)+ 8.86126436853789*pow(10,-7)*pow(t,5.0)-3.13621260398811*pow(10,-3)*pow(t,4.0)+5.91804640375908*pow(t,3.0)-6.27969461279651*pow(10,3)*pow(t,2.0)+ 3.55273415252714*pow(10,6)*t - 8.37223405676245*pow(10,8);
}
else
{

F_PROFILE(f,thread,position) = -9.51538261322402*pow(10,-23)*pow(t,6) + 8.26192751387975*pow(10,-18)*pow(t,5)-2.85237398505875*pow(10,-13)*pow(t,4)+4.97518353700886*pow(10,-9)*pow(t,3)-4.58733775886876*pow(10,-5)*pow(t,2)+ 2.10251137071757*pow(10,-1)*t +3.57252192344954*pow(10,2);

}

}

end_f_loop(f,thread)

}
Abhi.shek likes this.
mmunige is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
(ask) how to create UDF for inlet velocity profile sincity Fluent UDF and Scheme Programming 83 May 16, 2022 14:04
Free jet simulation msarkar OpenFOAM Running, Solving & CFD 39 May 11, 2021 14:21
[UDF] Relative coordinates in logarithmic velocity profile cfdworker Fluent UDF and Scheme Programming 25 July 13, 2017 04:44
setting a velocity profile like in Fluent gerado OpenFOAM 2 June 4, 2009 09:53
non uniform velocity profile at inlet hiba FLUENT 2 July 25, 2006 04:32


All times are GMT -4. The time now is 11:54.