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

turbine force_y vs dP * area

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 3, 2019, 00:02
Default turbine force_y vs dP * area
  #1
Senior Member
 
Svetlana Tkachenko
Join Date: Oct 2013
Location: Australia, Sydney
Posts: 415
Rep Power: 14
Svetlana is on a distinguished road
In ansys 19.2 the built in function

force_y()@turbine Default

and a similar manual calculation (here 'top' and 'bottom' are circular surfaces below and above the turbine)

(areaAve(Pressure)@bottom - areaAve(Pressure)@top ) * area()@top

give different results 2-3 times, inconsistently in different cases as it is not a linear relationship. Is this a known issue? How do I troubleshoot this? Can attach a small test case if anyone is interested.
Svetlana is offline   Reply With Quote

Old   May 3, 2019, 02:26
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,826
Rep Power: 144
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
your areaAve functions just average the pressure over the surface, they do not take into account direction. The force_y function only gets the force in the y direction. So your function is not working out the force in the y direction.
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.
ghorrocks is offline   Reply With Quote

Old   May 3, 2019, 02:31
Default
  #3
Senior Member
 
Svetlana Tkachenko
Join Date: Oct 2013
Location: Australia, Sydney
Posts: 415
Rep Power: 14
Svetlana is on a distinguished road
In this case my calculations should give larger values than CFX's force_y,
because they do not multiply by cos (direction angle) in each point.
However in my case the "dP * area" calculation gives results which are 0.3 to 0.7 of the force_y value predicted by CFX.
Svetlana is offline   Reply With Quote

Old   May 3, 2019, 02:34
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,826
Rep Power: 144
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
If you want us to help you, you are going to have to post an image of what you are analysing, a description of what the top and bottom surfaces are and a plot of the pressure distribution.
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.
ghorrocks is offline   Reply With Quote

Reply

Tags
lift and drag, post procesing, propeller, turbine

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
[ANSYS Meshing] How to properly mesh whole wind turbine (structured mesh on curved geometries) rusham ANSYS Meshing & Geometry 3 February 16, 2020 14:29
Modelling a rotating Savonius turbine BleuBleu ANSYS 3 March 5, 2019 07:01
fluen reference values for blade area and length nouman95 FLUENT 7 January 25, 2019 10:19
Turbine analysis of the turbocharger YOUNS CFX 1 September 21, 2018 06:36
Analysis of Tesla turbine shahryar FLUENT 5 February 1, 2018 08:33


All times are GMT -4. The time now is 04:56.