Adams model with tower from .mnf file in Ansys

Wind & Water Structural Analysis
1

Dear Jason,

I have to do a wind turbine model in Msc ADAMS with the tower imported as .mnf file created in Ansys. I have to use Aerodyn and interface it with my Adams model.
To do this I would like to create an equivalent Adams model from Fast v7 and then change the tower sections that Fast automatically create and use the tower .mnf file and constrain the flexiible tower al the nacelle. I am not sure if I can do this without modyfing the fortran routines that creates the “Adams.dll”, because I think that the “Fileds” that Fast creates automatically to model the tower flexibility (that I do no need using the .mnf file) are necessary. Is it true? Can I simply " cut" from the Adams model generated from Fast the tower sections and Fields or I need to modify the fortran routines?

Thank you!

2

Dear Alessandro,

You should be able to eliminate the tower-related FIELDs, which are only associated with the tower stiffness and damping. Likewise for the tower-related PARTs, MARKERs, GRAPHICS, JOINTs, and ARRAYs. The FAST-generated tower model in ADAMS does have GFORCE statements that interact with the Fortran routines, but these can probably be removed as well if you don’t want aerodynamic or hydrodynamic loads applied on the tower.

That said, I have not used MSC.ADAMS in years and I’m not sure what are the potential “issues” you may run into.

Best regards,

3

Dear Jason,

thank you for your answer!

I have another question. Do you think is it correct to use Adams model generated by Fast without using Aerodyn this way:

I want to model a small wind turbine without the drivetrain (GBratio =1). Instead of using Aerodyn I want to Apply my Adams model a rotor torque equivalent to Taero that I can compute this way:

  • I make the assumption that wind speed is constant: 6 m/s.
  • I have the generator electrical power-wind speed curve of my small turbine so I can calculate the generator power from the wind speed
  • Once I have the GenPwr I can calculate the GenTq from GenTq= GenPwr/rpm where rpm is the rotor rpm for that wind speed
  • Now I have Gear box efficency=100% and GBratio=1 so
    I can say thatI can apply a Taero in Adams : Taero=LssTq=HssTq=GenTq=GenPwr/Rpm that is an aerodynamic force that also considers the power curve. Is it right in your opinion?
4

Dear Alessandro,

Your approach sounds OK for steady-state analysis, but obviously the aerodynamic torque you compute this way would not be very useful for dynamic or transient analyses.

Best regards,