Force magnitude with moving mesh
Dear all,
I have further questions concerning the forces calculation with moving mesh. I'm simulating a rotating wind turbine. My problem is that the resulting forces seem to be too high (I have a wind turbine with power coefficient much higher than 1...). I was thinking maybe I had something wrong with my simulation, so I tried to run a simple 2D case of a cylinder with basically the same pre-processing data (cell size, boundary conditions, solver (pimpleFoam)). And I ended up with perfect values : I have a Cd error of 2%. So the simulation parameters seem to be in order. To sum up, I have run the following simulations with the same input parameters (the main difference is the moving mesh) :
Therefore the error seems to be coming from the moving mesh. So my question is : does anyone have experienced wrong forces calculations because of a moving mesh ? Or does anyone have experienced right forces calculations ? Should I trust my results and look somewhere else for the error (even though I've looked into almost everything else...) ? I would be glad if anyone having computed forces from a moving mesh could give their feedback (no matter wether it's positive or negative, I'd like to make myself an opinion on how confident I should be with my results) ! Thank you in advance for any answer! Daniel PS :
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I just found your thread and I am having the same problems that you have. The forces are calculated quite well for the non-moving cylinder but they are getting too high for a moving mesh.
I am going through the simulation for some days now and I can not find the problem. I was trying 3D LES, 2D URANS but the values of the force are higher than expected. Has anyone experienced similar behavior and found a solution to this? I am using the forceCoeffs function object in the controlDict file. |
Hi Bazinga,
I found the solution a long time ago but forgot to post it here. In my case, it was simply an error in the numerical procedure, I applied the wrong boundary condition for U on the paddle.
So the correct boundary condition for U on a moving solid with a no-slip condition is the movingWallVelocity. My input was: Code:
type movingWallVelocity; Regards, Daniel |
Thank you very much for your help. I made this exact mistake.
Best regards |
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