Learning Forum

[alfa_st]

Hi everyone. I'm trying to simulate HAWT with dynamic mesh and 6DOF method. Before trying this simulation, I've done sliding mesh simulation of a HAWT and Savonius VAWT, and succeed. Then I tried with dynamic mesh and 6DOF for the HAWT but failed. The turbine is bouncing. Then, I tried the same method for Savonius VAWT and Thank God its works. But, it is still not works for the HAWT, i have no idea for this issue. Would you all mind to help me solve this problem?Thank you very much, God Bless You Alln

[Rob]

Are you trying to look at the blade flex or just the rotation? Which solver?n

[alfa_st]

Hello Sir, thank you for your response. I'm trying to find out, the angular velocity and the torque of the turbine, by the effect of wind velocity. I'm using fluent. Thank you Sir. n

[Rob]

OK, I'd suggest using sliding mesh then and link the rotational velocity to the force on the blade. This can be done via a UDF or Expression. No need to use any remeshing and 6DOF is probably overkill. n

[alfa_st]

Thank you for the suggestion, Sir. But by using the sliding mesh, i don't get the actual angular velocity of the wind turbine. Because, we put the angular velocity as an input parameter. I'm sorry if i wrong Sir. What i need is, just put the wind velocity, moment of inertia, mass, material as input parameters then got the torque and angular velocity as the output. nFor my case, I've followed several identical tutorials on youtube. I followed every steps carefully. But i have no idea, why the turbine is rotating and bouncing at the same time. If you don't mind please check my set up on fluent.nn

[alfa_st]

Hello sir, after i watch again my animation result. actually the turbine is not bouncing. it is the ground of the fluent that moving up and down. i think it is happen, because of the dynamic mesh zone of the outer domain is set as deforming. this, issue won't happen if i put the turbine rotates on y axis. n

[Rob]

I'll leave Arrayto comment on the moving mesh bits, I know what it does but am less skilled in the how. nYou are correct in your comment re the sliding mesh. However, if you set the angular velocity as a function of the force on the blade which Fluent calculates you can then use the angular velocity value as an output. Exactly the same as the moving mesh approach but in a potentially much neater manner. n

[YasserSelima]

If your UDF is working with the vertical turbine ... it is not a UDF problem. nYou said the turbine is bouncing ... I suggest decreasing the time step as much as you can and try again. If it doesn't work, try giving it an initial rotational speed and leave it reach steady state.nAlso monitor the torque and the forces with different values of time steps. If the time step is large, you might get random values of the forcenn

[atefhimself]

I have the same request @alfa_st , if you could notice me when you solve the problem. I really appreciate your help n