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

Monitoring moment coefficients for multiple walls with different moment centers?

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 3, 2012, 14:23
Default Monitoring moment coefficients for multiple walls with different moment centers?
  #1
New Member
 
Ali
Join Date: Apr 2012
Location: India
Posts: 17
Rep Power: 14
ali.qasim is on a distinguished road
Hello

I have two vertical-axis wind turbines (2D) separated by a certain distance, rotating about their own axes.

I'd like to monitor the moment coefficients of their airfoils individually. I know I can do this through the Moment Monitor Dialog Box, but it doesn't allow me to choose different moment centers.

Obviously, the two turbines are not rotating about a single point, so I'd like to know how I can specify two points instead of just one.

Please help!

Thanks a lot in advance.

Ali
ali.qasim is offline   Reply With Quote

Old   May 3, 2012, 14:28
Default
  #2
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,752
Rep Power: 66
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
Quote:
Originally Posted by ali.qasim View Post
I'd like to monitor the moment coefficients of their airfoils individually. I know I can do this through the Moment Monitor Dialog Box, but it doesn't allow me to choose different moment centers.
Ali, create two separate Moment Monitors. You can then specify the axis individually for each monitor.
LuckyTran is offline   Reply With Quote

Old   May 3, 2012, 14:33
Default
  #3
New Member
 
Ali
Join Date: Apr 2012
Location: India
Posts: 17
Rep Power: 14
ali.qasim is on a distinguished road
Quote:
Originally Posted by LuckyTran View Post
Ali, create two separate Moment Monitors. You can then specify the axis individually for each monitor.
I didn't know that can be done! How do I do that?
ali.qasim is offline   Reply With Quote

Old   May 3, 2012, 15:03
Default
  #4
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,752
Rep Power: 66
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
Quote:
Originally Posted by ali.qasim View Post
I didn't know that can be done! How do I do that?
Uhh, create the first montior. Press ok (or enter if you're using TUI). Create another monitor, press ok. It is straightforward. You can create any number of monitors as you like.
LuckyTran is offline   Reply With Quote

Old   May 3, 2012, 15:23
Default
  #5
New Member
 
Ali
Join Date: Apr 2012
Location: India
Posts: 17
Rep Power: 14
ali.qasim is on a distinguished road
Quote:
Originally Posted by LuckyTran View Post
Uhh, create the first montior. Press ok (or enter if you're using TUI). Create another monitor, press ok. It is straightforward. You can create any number of monitors as you like.
Hmm. I don't see the option to create. I can only see 'Edit'.

Looks like it has to do with the version. I'm using 12. The Migration Manual for 14 says this is a new feature:
Quote:
Ability to set up multiple monitors in a single case for each one of the following: drag, lift, and moment
Can this still be done in 12? Perhaps through a different route?
ali.qasim is offline   Reply With Quote

Old   May 3, 2012, 15:36
Default
  #6
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,752
Rep Power: 66
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
Quote:
Originally Posted by ali.qasim View Post
Hmm. I don't see the option to create. I can only see 'Edit'.

Looks like it has to do with the version. I'm using 12. The Migration Manual for 14 says this is a new feature:


Can this still be done in 12? Perhaps through a different route?
ah-hah, I am using V14. Well in that case you are stuck. You really don't need it anyway. Any reason you need to monitor them this way? You can still print monitors by zone correct? For the sake of monitoring there is no need to have the correct axis. For the purpose of computation you can always report the moment later, or if you need to use the parallel axis theorem to calculate the correct moment.
LuckyTran is offline   Reply With Quote

Old   May 3, 2012, 16:15
Default
  #7
New Member
 
Ali
Join Date: Apr 2012
Location: India
Posts: 17
Rep Power: 14
ali.qasim is on a distinguished road
Quote:
Originally Posted by LuckyTran View Post
ah-hah, I am using V14. Well in that case you are stuck. You really don't need it anyway. Any reason you need to monitor them this way? You can still print monitors by zone correct? For the sake of monitoring there is no need to have the correct axis. For the purpose of computation you can always report the moment later, or if you need to use the parallel axis theorem to calculate the correct moment.
I'd like to compare the power coefficients - see how much of a difference there is between the upwind and the downwind VAWTs.

Yes, I can print the monitors per zone, but the axis for one will be wrong. And I don't want to do the computation twice.

Hmm.. parallel axis theorem. Rings a bell. You think that'll work for this? I'll have to go read up on that.
ali.qasim is offline   Reply With Quote

Old   May 3, 2012, 16:40
Default
  #8
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,752
Rep Power: 66
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
Quote:
Originally Posted by ali.qasim View Post
I'd like to compare the power coefficients - see how much of a difference there is between the upwind and the downwind VAWTs.

Yes, I can print the monitors per zone, but the axis for one will be wrong. And I don't want to do the computation twice.

Hmm.. parallel axis theorem. Rings a bell. You think that'll work for this? I'll have to go read up on that.
Just do the computation. It's only a few button clicks.
LuckyTran is offline   Reply With Quote

Old   May 3, 2012, 17:26
Default
  #9
New Member
 
Ali
Join Date: Apr 2012
Location: India
Posts: 17
Rep Power: 14
ali.qasim is on a distinguished road
Quote:
Originally Posted by LuckyTran View Post
Just do the computation. It's only a few button clicks.
It'd take me around 36 hours to get the complete computation done. So I'm just trying to solve for the first 10 iterations or so, and will then try to get a correlation between the moment coefficients.

Thanks a lot for your help. Appreciate it.
ali.qasim is offline   Reply With Quote

Reply

Tags
moment, turbine, vawt


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
Center of pressure (confirmation/question) scipy FLUENT 2 March 5, 2012 07:54
Force can not converge colopolo CFX 13 October 4, 2011 23:03
Writing Moment coefficient for different walls at different rotational axis harishameed33 Main CFD Forum 0 April 27, 2010 13:17
Residual moment coefficients are too high Agni CFX 1 October 13, 2008 18:50
Drag and moment coefficients Armando CFX 0 July 26, 2007 18:55


All times are GMT -4. The time now is 22:57.