VAWT Cl and Cd outputs

Thyriel · April 1, 2018, 13:22

Hi all,

For the past few months I have been setting up a study of a 2D VAWT for my thesis. After many bumps and walls I have finally been able to get the study going. I am unsure however of something.

I need to obtain the coefficient of drag and lift for the blades of the turbine, However, the mesh was created by rotating a quadrant of the three bladed VAWT, therefore I was unable to make each blade individually. My question is, since the htree blades are defined under the same BC, will the output form the force coefficients calculated by openfoam be for each individual blade? if not, How would you go about optaining Cl, Cp and thus the coefficient of Power for the turbine.

Thanks in advance guys

Marpole · April 12, 2018, 12:57

OpenFOAM doesn't know three or one blade. It simply integrate pressure/viscous on blade surface to get the lift and drag. So if you have three blades, it will give you lift/drag of all three blades. CL and Cd are obtained in the same mechanism. So be careful when you set Aref.

April 1, 2018, 13:22	VAWT Cl and Cd outputs	#1
Thyriel New Member Carlos Join Date: Nov 2017 Posts: 2 Rep Power: 0	Hi all, For the past few months I have been setting up a study of a 2D VAWT for my thesis. After many bumps and walls I have finally been able to get the study going. I am unsure however of something. I need to obtain the coefficient of drag and lift for the blades of the turbine, However, the mesh was created by rotating a quadrant of the three bladed VAWT, therefore I was unable to make each blade individually. My question is, since the htree blades are defined under the same BC, will the output form the force coefficients calculated by openfoam be for each individual blade? if not, How would you go about optaining Cl, Cp and thus the coefficient of Power for the turbine. Thanks in advance guys

April 12, 2018, 12:57	VAWT Cl and Cd outputs	#2
Marpole Senior Member Charles Join Date: Aug 2016 Location: Vancouver, Canada Posts: 148 Rep Power: 9	OpenFOAM doesn't know three or one blade. It simply integrate pressure/viscous on blade surface to get the lift and drag. So if you have three blades, it will give you lift/drag of all three blades. CL and Cd are obtained in the same mechanism. So be careful when you set Aref.