wind turbine simulation, Ansys Post results question

Laions · August 26, 2010, 06:32

Hi,

I've simulated 1/3 of a wind turbine (just one blade). I can not get the correct result...I belive the boundary conditions are OK as well as the convergence (residual set to 1e-5). The mesh is not fine enough but that's not the problem as it is fine on the blade.
When I use the calculator to extract the torque from the y axis (axis of rotation of my wind turbine) I've just got around 2000 Nm

when the torque expected will be around 55000 Nm (it's the NORDTANK 500-41)...any advice will be much appreciated.

Cheers

ghorrocks · August 26, 2010, 07:38

Have you checked the basics?
http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

stumpy · August 26, 2010, 17:05

I assume you have a rotating domain, and haven't just assigned a wall velocity on the boundary condition instead?

Laions · August 26, 2010, 20:36

Thanks ghorrocks for your suggestion, I've already checked the basics though.

Thank you stumpy, I do have a rotating domain for the turbine interfacing as a frozen rotor with the big domain. I'm quite sure that the boundary conditions are not the problem. That is why I'm a bit desperate...I even thought that maybe the direction of the torque is not in the axis of rotation but that does not make sense.

Thanks to both for replying.

paulo · August 27, 2010, 16:46

Hi,

Have you made a mesh convergence study of your problem. This can change the result a lot.

Best Regards,

Paulo Rocha

Laions · August 28, 2010, 04:15

Thanks Paulo, I haven't made a convergence study, I thought that if the mesh was fine enough around the turbine's blade was sufficient. Besides, I can not play much more with the mesh as it has reached 2.5milion of elements (with both domains) and my computer is limited, but I´ll follow your advise and try it, thanks again.

Best wishes

ghorrocks · August 28, 2010, 07:36

A mesh refinement study is a very basic check which should always be done in CFD. Clearly you did not even read the link I previously posted.

You can do mesh refinement studies which only coarsen the mesh. This will tell you whether the simulation you plan is possible with the computers you have available.

harjeetmaan · September 20, 2011, 06:13

I am working on the simulation and modeling of wind turbines. Is anybody can help me to find out the quantity of backflow in the wind turbine and how to model the same using FLUENT.

Harjeet

August 26, 2010, 06:32	wind turbine simulation, Ansys Post results question	#1
Laions New Member Join Date: Aug 2010 Posts: 3 Rep Power: 16	Hi, I've simulated 1/3 of a wind turbine (just one blade). I can not get the correct result...I belive the boundary conditions are OK as well as the convergence (residual set to 1e-5). The mesh is not fine enough but that's not the problem as it is fine on the blade. When I use the calculator to extract the torque from the y axis (axis of rotation of my wind turbine) I've just got around 2000 Nm when the torque expected will be around 55000 Nm (it's the NORDTANK 500-41)...any advice will be much appreciated. Cheers Last edited by Laions; August 26, 2010 at 06:48. Reason: I put can instead of can not, sorry about that

September 20, 2011, 06:13	Modeling Of wind turbine.	#8
harjeetmaan New Member Harjeet Singh Mann Join Date: Jul 2011 Location: Bathinda (Punjab) Posts: 7 Rep Power: 15	I am working on the simulation and modeling of wind turbines. Is anybody can help me to find out the quantity of backflow in the wind turbine and how to model the same using FLUENT. Harjeet

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August 26, 2010, 07:38		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	Have you checked the basics? http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

August 26, 2010, 17:05		#3
stumpy Senior Member Join Date: Apr 2009 Posts: 531 Rep Power: 21	I assume you have a rotating domain, and haven't just assigned a wall velocity on the boundary condition instead?

August 26, 2010, 20:36		#4
Laions New Member Join Date: Aug 2010 Posts: 3 Rep Power: 16	Thanks ghorrocks for your suggestion, I've already checked the basics though. Thank you stumpy, I do have a rotating domain for the turbine interfacing as a frozen rotor with the big domain. I'm quite sure that the boundary conditions are not the problem. That is why I'm a bit desperate...I even thought that maybe the direction of the torque is not in the axis of rotation but that does not make sense. Thanks to both for replying.

August 27, 2010, 16:46		#5
paulo Member Paulo Alexandre Costa Rocha Join Date: Mar 2009 Posts: 71 Rep Power: 17	Hi, Have you made a mesh convergence study of your problem. This can change the result a lot. Best Regards, Paulo Rocha

August 28, 2010, 04:15		#6
Laions New Member Join Date: Aug 2010 Posts: 3 Rep Power: 16	Thanks Paulo, I haven't made a convergence study, I thought that if the mesh was fine enough around the turbine's blade was sufficient. Besides, I can not play much more with the mesh as it has reached 2.5milion of elements (with both domains) and my computer is limited, but I´ll follow your advise and try it, thanks again. Best wishes

August 28, 2010, 07:36		#7
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	A mesh refinement study is a very basic check which should always be done in CFD. Clearly you did not even read the link I previously posted. You can do mesh refinement studies which only coarsen the mesh. This will tell you whether the simulation you plan is possible with the computers you have available.