Search found 21 matches

by Saptarshi.Sarkar
Mon Aug 27, 2018 5:06 am
Forum: NWTC Wind Data
Topic: Offshore Wind Data
Replies: 11
Views: 9576

Re: Offshore Wind Data

Thank you so much, Dr Stewart. Your clarifications are of great help to me.

-Saptarshi
by Saptarshi.Sarkar
Fri Aug 24, 2018 8:43 am
Forum: NWTC Wind Data
Topic: Offshore Wind Data
Replies: 11
Views: 9576

Re: Offshore Wind Data

Dear Dr Stewart, I have a couple more queries if you don't mind. If I want to refine the bins (make the bins smaller in size) can I interpolate between the available data? I have observed that in some columns, especially toward the boundary of the tables the value change abruptly from one cell to an...
by Saptarshi.Sarkar
Fri Aug 17, 2018 2:25 am
Forum: NWTC Wind Data
Topic: Offshore Wind Data
Replies: 11
Views: 9576

Re: Offshore Wind Data

Hi Gordon,

Thanks a lot, it clears up all my doubts and for going through the hassle of digging out the old files. I'm trying to do a fatigue study and you have in fact answered my doubt regarding assigning the probability to those bins.

Thanks again,
Saptarshi
by Saptarshi.Sarkar
Wed Aug 15, 2018 7:31 am
Forum: NWTC Wind Data
Topic: Offshore Wind Data
Replies: 11
Views: 9576

Re: Offshore Wind Data

Thanks a lot. I will wait for his reply.

Saptarshi
by Saptarshi.Sarkar
Wed Aug 15, 2018 3:55 am
Forum: NWTC Wind Data
Topic: Offshore Wind Data
Replies: 11
Views: 9576

Re: Offshore Wind Data

Hi all, I trying to use the metocean data provided in https://nwtc.nrel.gov/metocean for my research. However, I'm facing two issues. Firstly and most importantly, I have been trying to match the various pdfs for East Coast data with the plots provided in the paper: https://onlinelibrary.wiley.com/d...
by Saptarshi.Sarkar
Thu Jun 21, 2018 3:58 am
Forum: Rotor Aerodynamics
Topic: Wake-Skewed Angle Model
Replies: 8
Views: 7322

Re: Wake-Skewed Angle Model

Dear Dr. Jonkman,

Thanks a lot for clarifying this.

Saptarshi
by Saptarshi.Sarkar
Wed Jun 20, 2018 8:25 am
Forum: Rotor Aerodynamics
Topic: Wake-Skewed Angle Model
Replies: 8
Views: 7322

Re: Wake-Skewed Angle Model

Dear Dr. Jonkman, For the Pitt and Peter's skewed wake correction is the angle between the vector normal to the rotor plane and the wind vector calculated at every blade section? What I mean is, under turbulent wind every blade section will have a different wind vector while the normal vector to the...
by Saptarshi.Sarkar
Thu Feb 01, 2018 10:35 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 331
Views: 52666

Re: FAST theory manual

Dear Dr. Jonkman,

Thank you for the comments. I'll try that.

Saptarshi
by Saptarshi.Sarkar
Thu Feb 01, 2018 7:16 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 331
Views: 52666

Re: FAST theory manual

Dear Dr. Jonkman, From FAST I've used the linearization analysis to calculate the natural frequencies. From my model, I'm just using the elastic stiffness and the modal mass to calculate the frequency. Now I understand that the stiffness from FAST linearization will be higher/lower due to centrifuga...
by Saptarshi.Sarkar
Thu Feb 01, 2018 3:05 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 331
Views: 52666

Re: FAST theory manual

Dear Dr. Jonkman, I'm trying to match the modal frequencies of my model to that of FAST. For the 1st mode (both tower and blade flapwise) my frequencies are matching. But, for the second mode (again both tower and blade flapwise) my modal frequencies are less compared to that of FAST. For example, f...
by Saptarshi.Sarkar
Mon Jan 22, 2018 4:17 pm
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 331
Views: 52666

Re: FAST theory manual

Dear Dr. Jonkman,

In FAST are centrifugal stiffening effect and gravitational stiffening/softening effect added separated? Or does it come inherently from the formulation?

Thanks,
Saptarshi
by Saptarshi.Sarkar
Mon Sep 25, 2017 2:42 pm
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 331
Views: 52666

Re: FAST theory manual

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
by Saptarshi.Sarkar
Mon Sep 25, 2017 11:10 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 331
Views: 52666

Re: FAST theory manual

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 stiff...
by Saptarshi.Sarkar
Tue Sep 12, 2017 7:51 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 331
Views: 52666

Re: FAST theory manual

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
by Saptarshi.Sarkar
Mon Aug 28, 2017 5:23 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 331
Views: 52666

Re: FAST theory manual

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...

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