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Jervds March 4, 2008 11:03

Cel expressions for trasient problem
Hello all,

I'm new in CFD, I'm trying simulate a small wind turbine, where its velocity should be constant. But the velocity control is made from the queue of the turbine that has the capacity to blend and change the direction of incidence of the wind, which causes the desacceleration the turbine.

Right now, I'm in the first step of the problem. Using a value of wind, I want to find a constant velocity of the turbine in a transient system, changing the wind incidence's angle, if necessary, when the angular velocity of the turbine reaches a standard value.

I tried with cell expressions like Vel=Vel+∆V, where ∆V is calculated in each time step. I'm using torque to calculate the acceleration and I have an expression to change de wind incidence's angle. But an error message appears:

"A cyclic dependency between expressions has been detected while processing the expression assigned to 'Angular Velocity'. The cycle detected is as follows (there may be others): Vel -> Vel."

I tried to put others expressions but it didn't work… Can this problem only be solved with fortran routine or its possible with cel expressions?

Thanks for your help


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