Learning Forum

[amind]

Hello everyone

I am simulating a 2D vertical axis wind turbine in ANSYS Fluent software. A schematic of this turbine can be seen in Figure1.

Figure1:

[Rob]

You need a round separate fluid zone for each foil. You then set the reference system for each fluid. Read up on sliding mesh, and make sure you understand absolute and relative in the cell zone panels.

[amind]

Thanks Rob
I followed your advice. I used sliding mesh for the turbine rotor (large circle).


I also created a circular zone around each airfoil and set them as "relative" to the large circle in the "cell zone panel".

But I still do not know how I can set a "separate coordinate system" for each "zone".
In other words, I do not know in which panel of Fluent software I can adjust the settings for the new coordinate systems?

[Rob]

Cell zone as you've shown above. Each rotating zone needs it's own axis and speed. For the airfoil zones use the value at the start of the calculation, ie on the mesh you read in. Make sure you save the case somewhere safe (export if you're using Workbench) as errors will result in the airfoils orbiting the main rotation zone: it's very pretty but not overly useful as a simulation and fixing it at that stage is near to impossible.

[amind]

Thanks Rob, but I do not want airfoils to rotate; I just want to have a local coordinate system (x, y) on each airfoil.
Because I want to apply a "source term" to each airfoil using "Named Expression" in the x and y directions. (A body force in the x and y directions is applied to each airfoil to control the flow separation by increasing the momentum of the boundary layer)
Fluent software applies these source terms in the (X, Y) direction of the global coordinate system, but I want these forces to be applied in the (x, y) direction of local coordinate systems on each airfoil.

[Amine Ben Hadj Ali]

You cannot use that till now. There is a workaround to create different reference frames and cerate profiles associated with these new reference frames or even do coordinate transformation with this new reference frames (this will require some UDF for now). So for now unfortunately usage of reference frame is limited.