Will initial condition TTDspFA in Elastodyn lead to intial displacement and deflection of blade?

Dear forumers,

When I run the glue code, I am curious that will intial condition TTDspFA defined in Elastodyn lead to intial displacement and deflection of blade? Could you please correct me if I am wrong?

  1. As both tower and blade are flexible (if all DOF relevant to both tower and blade are enabled), I guess tower will initially deflect based on initial TTDspFA value.

  2. I also guess rotor plane of blades will rigidly rotate and displace as tower top has displaced.

  3. But I am not confirmed whether blade will also deflect initially as a result of initial TTDspFA.


Dear @Ran.Tu,

I agree with your points 1-2. Setting a nonzero initial TTDspFA will only initialize the tower-top fore-aft deflection, not the blade-tip deflection. However, the ensuing dynamic response caused by the initial tower-top deflection may very well induce motion of the blade during the start-up transient phase of the simulation, e.g., through inertial forces. Gravitational forces also play a role in the start-up transient of the tower and blade deflections.

Best regards,

Dear Jason,

Thanks for you explanation.

Now my understanding is nozero inital TTDspFA will not lead to blade deflection. But blade, hub and nacelle may displace after assiging nozero inital TTDspFA (before simulation starts). so the start-up transient in this situation will be different from that with zeroed inital TTDspFA.


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