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

simulation of a vibrating surface

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   February 8, 2010, 11:24
Default simulation of a vibrating surface
  #1
Member
 
Ivan
Join Date: Aug 2009
Posts: 63
Rep Power: 16
IvanCFD is on a distinguished road
Hi,

I have come across with a problem I have to solve and I don't really know how to start.

I have to simulate in Fluent 2D a vibrating surface (vibrating line).

Imagine a box (a square), the bottom edge of the square has to move up and down, not like a piston, but like a snare. That is, the ends of the edge are clamped (fixed) and the line deforms like half period of a sine wave, i.e. with its maximum deformation at the middle of the edge.

I have got a script in Matlab which simulates the up-and-down motion of each node of that edge over time, and I was wondering how I can implement it into Fluent.

Plus, I don't know if the mesh of the model has to include nodes below that bottom edge in order for Fluent to simulate those instants at which the nodes of the vibrating edge are below their rest position.

I'd really appreciate any hint about this problem.

Many thanks beforehand,

Ivan.
IvanCFD is offline   Reply With Quote

Old   February 8, 2010, 14:47
Default
  #2
Member
 
Neil
Join Date: Jun 2009
Location: The Moon
Posts: 42
Rep Power: 16
Trev is on a distinguished road
Hi,

I suggest you look at the Fluent tutorial with the oscillating membrane as it describes exactly what you are trying to attempt and you can easily adapt the UDF. With regards to the mesh you will need a tri mesh scheme so that the spring analogy dynamic mesh option can be activated.

Neil
Trev is offline   Reply With Quote

Old   February 8, 2010, 14:52
Default
  #3
Member
 
Ivan
Join Date: Aug 2009
Posts: 63
Rep Power: 16
IvanCFD is on a distinguished road
Hi Neil,

thanks a lot for your rapid reply (that was really quick!).

I don't have the Fluent tutorial. Would you mind to give some hint about where to find it? At the moment I am looking through the Fluent 6.3 UDF Manual. It;s the only thing I've got.

Cheers,

Ivan.
IvanCFD is offline   Reply With Quote

Old   February 8, 2010, 15:02
Default
  #4
Member
 
Ivan
Join Date: Aug 2009
Posts: 63
Rep Power: 16
IvanCFD is on a distinguished road
Hi again Neil,

do you mean the Wave Tank tutorial from the following link?

http://www.ansys.com/academic/academ...ials-popup.asp

Ivan.
IvanCFD is offline   Reply With Quote

Old   February 8, 2010, 15:39
Default
  #5
Member
 
Neil
Join Date: Jun 2009
Location: The Moon
Posts: 42
Rep Power: 16
Trev is on a distinguished road
Its a different one to that, post your email address then I can send you the files.

Neil
Trev is offline   Reply With Quote

Old   February 8, 2010, 15:47
Default
  #6
Member
 
Ivan
Join Date: Aug 2009
Posts: 63
Rep Power: 16
IvanCFD is on a distinguished road
iroldanb@gmail.com

Ivan.
IvanCFD is offline   Reply With Quote

Old   February 8, 2010, 16:04
Default
  #7
Member
 
Neil
Join Date: Jun 2009
Location: The Moon
Posts: 42
Rep Power: 16
Trev is on a distinguished road
I tried emailing several times but it never got through so here is a download link instead. Hope this helps.

http://www.easy-share.com/1909237722/mdm-flex-files.zip

Neil
Trev is offline   Reply With Quote

Old   February 13, 2010, 19:03
Default
  #8
Member
 
Ivan
Join Date: Aug 2009
Posts: 63
Rep Power: 16
IvanCFD is on a distinguished road
Hello Neil,

first of all, thanks a lot, because that tutorial you sent me about, amongst other things, a membrane oscillating sinusoidally is simply great. Actually that case is even more complicated than mine.

Therefore, I started to replicate that tutorial. Everything was alright until I get the moment of building the UDF...

I'm going through a nightmare trying to make the UDF work:

When I loaded the UDF for the first time I got the following message:

- "nmake" not recognized as an internal or external command, operable program or batch file.

I saw out there that it is an issue related to the interaction between Fluent and Visual Studio To solve it, during the installation process, one needs to select the "register environment variables" option. However, I didn't saw such option during the Fluent installation. This is what I did step by step:

1) Install full Microsoft Visual Studio 2008.

2) Install Windows-based Fluent.

3) Go to "Start" --> "All Programs" --> "Fluent Inc Products" --> "Fluent 6.3.26" --> "Set Environment"

After doing all that, I still couldn't load my UDF. Same error message.

Then, I downloaded nmake.exe and installed at \Fluent.Inc\fluent6.3.26\ntx86 and also at WINDOWS\system32, I opened a command prompt and executed nmake. After doing all this, back on Fluent I was able to get rid of the nmake error message.

However I now get another error message:

Opening library "libudf"...
Error: open_udf_library: (...)


I installed Visual Studio 2008 and I didn't see at any step whether path to be set or not. But after doing the "Set Enviroment" thing mentioned above I checked that PATH is at ntx86 indeed.

Would you know what I'm missing?

Many thanks beforehand,

Ivan.
IvanCFD is offline   Reply With Quote

Old   February 15, 2010, 15:24
Default
  #9
Member
 
Neil
Join Date: Jun 2009
Location: The Moon
Posts: 42
Rep Power: 16
Trev is on a distinguished road
You need to open Fluent through the visual studio command prompt.

Neil
Trev is offline   Reply With Quote

Reply

Tags
fluent, snare, time, transient simulation, vibrating

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
Help needed with free surface simulation Mark CFX 4 October 27, 2006 13:07
CFX bubble simulation with free surface model adma CFX 6 February 3, 2006 12:17
Free surface flow simulation question Jane Luo FLUENT 1 April 23, 2004 05:26
turbulence simulation and free surface vineet Main CFD Forum 3 September 23, 2001 12:25
CFX4.3 -build analysis form Chie Min CFX 5 July 13, 2001 00:19


All times are GMT -4. The time now is 17:26.