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-   -   How to generate a wave in Fluent? (http://www.cfd-online.com/Forums/fluent/62766-how-generate-wave-fluent.html)

 gholamghar March 19, 2009 04:09

How to generate a wave in Fluent?

1 Attachment(s)
Hello
I want to generate a wave in Fluent.anybody knows how i should do this?
i have heard this should be done with UDF writing.is this right?
thanks

 paka March 20, 2009 02:46

Hello stranger,

Yes you should use UDF function, means write your own routine. Depends what kind of wave you need to generate. There is one of the tutorials online, I believe it is in student section... Let me check it online...

OK. I found one of the links, here it is, direct link to the PDF with tutorial.
http://willem.engen.nl/uni/fluent/do...ernal/wave.pdf

Hope it helps. If you have some more questions shoot, I'll try to help.

PS. What is a little bit strange, if you test the same routine in pure C, you will get ALMOST the same paddle displacement numerical values as those from Fluent C routine, but slightly, by a tiny bit off from the ones from original C... like 0.00001. Overall displacement plots overlap.

 ekakavand November 27, 2009 15:51

generate wave

hi
this is a late answer but you can find it in this link:
http://www.fluent.com/software/sf_me...orial_wave.htm

and search (fluent tutorial generate wave in tank) you can find a pdf file that explain how you can solve your problem.

best regards,
elahe

 WSWGg December 25, 2009 04:28

It's not necessary to define moving wall using UDF. Why???!!! Aren't you afraid of possible problems with your grid?!
Just define velocity components: horizontal and vertical - and water free level using UDF. I think it's simpler. If you need I can send you my UDF file.
Also, don't forget about wave reflection from outlet boundary because of using pressure-outlet boundary conditions.

 ekakavand December 28, 2009 03:43

Hi WSWGg,

do you mean i should patch water level in the first and introduce a periodic horizental velocity to fluent? do i undrestant right?

if not please explain it for me a little more,

can i get your udf file,too?

all the best,
elahe

 WSWGg December 28, 2009 05:01

Of course, you should patch water level in the first!
Ok, I'll do this, I'll send you my UDF, but after January 1st, ok?
I've got a little problems at the moment.

 ekakavand December 28, 2009 07:03

Thank you so much WSWGg,

all the best,
elahe

 arampath January 5, 2010 07:17

Hi,
i am also try to simulate wave by introducing velocity inlet (linear theory)
and its work fine with me.
now i want to simulate (wave carry with mean current) but in this case i don't know how to set the boundary conditions.

any help would be highly appreciate

 novice January 5, 2010 08:43

Hi WSWGg,

Can you please send the UDF to me also. i want to define the velocity at the inlet using a UDF.

 ekakavand January 9, 2010 17:51

Quote:
 Originally Posted by WSWGg (Post 241027) Of course, you should patch water level in the first! Ok, I'll do this, I'll send you my UDF, but after January 1st, ok? I've got a little problems at the moment.

hi WSWGg
i hope to be solved your problem,

all the best
elahe

 WSWGg January 11, 2010 08:34

Arampath and Ekakavand, check your e-mails, I've just sent my UDF file, like had promised.
Novice, excuse me, but I don't understand you post. You simulated wave using linear wave theory making boundary conditions on velocity components on enter border, am I right? So, what's the problem?

 mahbube March 9, 2010 09:53

Hi
can anyone help me to write a UDF for the creation of a sinusoidal wave at the end of a model square tank(model basin)(2-D)?
thanks.

 ekakavand March 9, 2010 10:06

Quote:
 Originally Posted by mahbube (Post 249166) Hi can anyone help me to write a UDF for the creation of a sinusoidal wave at the end of a model square tank(model basin)(2-D)? thanks.
Hi

can you send me your email?
my email is here... you can see it.

best
elahe

 mahbube March 13, 2010 04:53

Quote:
 Originally Posted by paka (Post 210084) Hello stranger, Yes you should use UDF function, means write your own routine. Depends what kind of wave you need to generate. There is one of the tutorials online, I believe it is in student section... Let me check it online... OK. I found one of the links, here it is, direct link to the PDF with tutorial. http://willem.engen.nl/uni/fluent/do...ernal/wave.pdf Hope it helps. If you have some more questions shoot, I'll try to help. PS. What is a little bit strange, if you test the same routine in pure C, you will get ALMOST the same paddle displacement numerical values as those from Fluent C routine, but slightly, by a tiny bit off from the ones from original C... like 0.00001. Overall displacement plots overlap.

hello paka
i have used udf(DEFINE-CG) for writing udf in the tutorial wave generation in a tank,but i dont know what to write vel?i dont know how to define vel for this waves?.

 lordg April 19, 2010 04:05

Wave and breakwaters

Quote:
 Originally Posted by WSWGg (Post 241027) Of course, you should patch water level in the first! Ok, I'll do this, I'll send you my UDF, but after January 1st, ok? I've got a little problems at the moment.
Hi everyone...
i am trying to simulate the turbulent waves and scouring in front of breakwaters...
the wave simulation works fine with the laminar flow option but when i switch to turbulent flow (k-e or k-o) the solution always diverges and i get no wave profile...
any help with that will be appriciated.

and WSWG if i could get your UDF also it'd do me great help as i am new to UDFs. my email is gsoydinc@parkinsaat.com

Thnx.

gok

 pranab_jha April 21, 2010 12:34

Quote:
 Originally Posted by WSWGg (Post 240909) It's not necessary to define moving wall using UDF. Why???!!! Aren't you afraid of possible problems with your grid?! Just define velocity components: horizontal and vertical - and water free level using UDF. I think it's simpler. If you need I can send you my UDF file. Also, don't forget about wave reflection from outlet boundary because of using pressure-outlet boundary conditions.
Hi WSWGg,
I am trying to model waves on water surface inside a pipe flowing with air and water. I have already simulated the stratified flow, but do not know how to generate a wave using a UDF coz I have no prior experience in writing a UDF. I want to generate a wave and then observe it with different phase velocities. Can you please send me your UDF so that I can learn from it.

Thanks,
Pranab

 Randre April 21, 2010 12:56

There are many Thesis online wich have UDFs regarding wave profiles.

With just a quick search:

The wave theory chosen for the UDF of thesis above is Stokes 2nd Order. If you want another one like Linear just change the equations

 pranab_jha April 23, 2010 09:38

Quote:
 Originally Posted by WSWGg (Post 256064) I've got your letter, have looked at your picture and want to tell you next: your task as you understand is full 3D problem and it can't be reduce to plane-parallel case which allows to consider only 2D problem. By the moment I've handled only 2D problem so I don't think I or my UDF can help you. But one advice maybe would be beneficial to you, try to generate sinusoidal wave by harmonic wall motion. M-m, you know, at the moment I even don't know is it possible to generate wave using only UDF function in your case - sorry. Good luck.
Hi WSWGg,

 Zaktatir June 24, 2010 11:12

can u send me the udf file please (nevertheless i am using CFX) but just for interest of introducing some perturbation into my stratified flows

 trantoan2008 July 18, 2011 04:39

Hi WSWGg,

Can you send me your UDFs file? By the way, how can I plot wave elevation coresponding to time in FLuent S/W?