|
[Sponsors] |
Simulation with a rotating frame within another? |
|
LinkBack | Thread Tools | Search this Thread | Display Modes |
April 18, 2013, 07:13 |
Simulation with a rotating frame within another?
|
#1 |
Senior Member
Stuart
Join Date: Jul 2009
Location: Portsmouth, England
Posts: 733
Rep Power: 25 |
Hi,
Is it possible to model this scenario in CFX? A vertical axis wind turbine which has an odd number of blades (seen topics about this before). So this would be a rotating domain containing the blades inside a stationary domain for the surroundings connected via a GGI. The rotation of the turbine is only driven by the wind speed, it's not a known value beforehand. However, the extra bit I need to include is that each blade constantly pitches (about a hinge axis fixing the blade to the hub) during a single 360 degree rotation of the turbine. The pitching behaviour is only due to the aerodynamic loads on the blade which change depending upoon if the blade is advancing or retreating relative to the freestream wind. This blade pitching would also contribute to the speed of the entire turbine. I guess this would involve putting each blade in a rotating domain which are themselves inside the turbine's rotating domain, all connected with GGIs. Thanks. |
|
August 22, 2016, 06:08 |
|
#2 |
Member
Ruud Caljouw
Join Date: Dec 2012
Posts: 45
Rep Power: 13 |
Hi siw,
did you eventually solve this problem? I am also working on a similar problem. Thanks |
|
August 22, 2016, 09:45 |
|
#3 |
New Member
Join Date: Aug 2016
Posts: 17
Rep Power: 9 |
I don't think there is any necessity to use one rotating frame within another. this probably a fluid-structure integrated problem.
|
|
August 22, 2016, 19:59 |
|
#4 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
You can't put a rotating frame of reference inside another one. In CFX RFR needs a fixed rotation axis. So you are going to have to do this by moving mesh.
Also I would not recommend doing this as a rigid body or FSI simulation to get the rotation speed. Only use FSI if you are modelling the blade deflection due to aerodynamic loads. It is far easier to get the rotation speed by running a series of assumed and fixed rotation speeds and establishing the system torque versus speed characteristic. Then you can interpolate to zero net torque based on the system load. This approach requires several simple simulations. |
|
August 23, 2016, 02:57 |
|
#5 | |
Member
Ruud Caljouw
Join Date: Dec 2012
Posts: 45
Rep Power: 13 |
Yes, I noticed this. How would that work with the moving mesh.
I read on another website the following text on how to do this? Would you agree with this. My (brief) efforts to apply this have not been successful yet Quote:
|
||
August 23, 2016, 05:59 |
|
#6 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
I don't understand the quote's second paragraph. The domain which has a simple rotation about a fixed axis should be made a rotating domain and the domains which have a moving rotation axis have to be moving mesh. I can't see how it can be done any other way.
Other than the quote seems correct. |
|
August 23, 2016, 14:37 |
|
#7 |
Senior Member
Stuart
Join Date: Jul 2009
Location: Portsmouth, England
Posts: 733
Rep Power: 25 |
||
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
UDF for defining a body force in Singel ROtating Reference Frame | teymourj | Fluent UDF and Scheme Programming | 9 | August 18, 2016 15:33 |
Rotating rotor inside a frame | wllmk1 | OpenFOAM | 38 | April 8, 2014 06:58 |
Moving Meshes or Rotating Refrence frame is suitable for Rotating Blades? | arash_7444 | FLUENT | 3 | March 21, 2011 01:07 |
question about governing equation in CFX using rotating/non rotating reference frame | rystokes | CFX | 0 | January 12, 2010 06:14 |
Gravity in single rotating reference frame | QinxueTan | FLUENT | 0 | May 7, 2008 06:59 |