Respected Dr. Jonkman,
I was going through the Drivetrain modeling from “Unofficial FAST theory manual”. There is a term T^{Gen} used which represents a positive load extracted. This quantity is represented as a function of Gear Box Ratio x Angular speed and time. So, for a wind turbine of with constant power output of 5MW can this quantity be represented as:
T^{Gen} = 5MW/GBRatio/LSSTipVxa(in rad/s).
Thank you,
Saptarshi
Dear Saptarshi,
T^Gen in the “Unofficial FAST Theory Manual” is a variable that refers to the generator torque computed by the generator or torque-controller models.
Your equation likely applies under steady-state conditions, except that it is missing possible effects from gearbox efficiency/friction (which reduces the torque in the high-speed shaft relative to the low-speed shaft) and generator efficiency (which means that more than 5-MW of mechanical power are needed to generate 5-MW of electrical power). Under transient conditions, the equation will depend on the generator or torque-controller settings.
I hope that helps.
Dear Dr. Jonkman,
In FAST, for aeroelastic simulation the blade velocities in which reference frame are returned to AeroDyn? Also, are the returned velocities calculated from the hub (i.e. HvS1(r)) or are they calculated in the inertial reference frame (i.e. EvS1(r))?
Thank you,
Saptarshi
Dear Saptarshi,
In FAST, all positions and velocities transferred to AeroDyn are expressed in the inertia frame coordinate system.
I hope that helps.
Best regards,
Dear Dr, Jonkman,
Due to the mode shapes of the blades the cross flapwise blade stiffness between mode 1 and 2 (k12_B1F1) that I’m calculating is coming out as negative. Do you remember if this is the case and the same is also used in FAST or not?
Is there a way to extract the structural modal stiffness or frequencies from FAST?
Thank you,
Saptarshi
Dear Saptarshi,
I would expect a quite small cross-stiffness term between the first and second flapwise-bending modes of the blades (only nonzero if the mode shapes are not orthogonal).
Yes, you can extract the full-system mass, stiffness, and damping matrices, as well as the full-system natural frequencies through a FAST linearization analysis.
Best regards,
Dear Dr. Jonkman,
By my last question I meant can the cross-stiffness term be negative? I was expecting a small positive value but I’m getting a negative value. So, is a negative value possible or should it always be positive? And, in FAST is the value positive or negative?
Thank you,
Saptarshi
Dear Saptarshi,
I looked at one of the models I linearized in the past and the cross-stiffness term was negative (but much smaller in magnitude than the diagonal).
Best regards,
Dear Jason
I have already read the relevant topic,and i want to obtain more information.
Could you sent the “Unofficial FAST Theory Manual” to me ?
My e-mail address is " wmynike1993@gmail.com"
Thank you very much indeed
Best regards
Sent.
Dear Jason,
Could you please send me a copy of unofficial FAST theory manual? My email is e.mohamadi66@gmail.com
Thanks a lot.
Ebrahim
Sent.
Dear Jason,
I have read the relevant topics, and I would like to have more information.
Could you please send me the “Unofficial FAST Theory Manual” ?
My e-mail address is " yukaiw@gmail.com".
Thank you very much for your help!!
Best regards
Sent.
Dear Jason,
Could you please send me the latest copy of unofficial FAST theory manual? My email is musavi6889@yahoo.com
Thank you.
Mahmoud
NTU, Taiwan
Sent.
Dear Jason Jonkman,
I would also like to receive the unofficial theory manual for FAST. My email is kamranali406@sjtu.edu.cn
Thank you
Sent.
Dear Dr Jonkman,
Can you please send me the “Unofficial FAST Theory Manual” as well?
zcheng0411@gmail.com
Thank you,
Kind regards,
ChengZhang
Sent.