## Search found 21 matches

Mon Jul 24, 2017 10:05 pm
Forum: Rotor Aerodynamics
Topic: Question about NREL Phase VI Power Data
Replies: 11
Views: 10159

### Re: Question about NREL Phase VI Power Data

I see, thanks sir!
Thu Jul 13, 2017 5:03 am
Forum: Rotor Aerodynamics
Topic: Question about NREL Phase VI Power Data
Replies: 11
Views: 10159

### Re: Question about NREL Phase VI Power Data

Any idea where to get Sequence S data?
Tue May 16, 2017 1:45 am
Forum: Computer-Aided Engineering Software Tools
Topic: AeroDyn Outputs
Replies: 14
Views: 4825

### Re: AeroDyn Outputs

Sir,

From the Aerodyne Theory Manual (Moriarty and Hansen, 2005), is it ok to solve Equations 26/27 (a) and 28(a') without using Newton Raphson, Fixed-Point or Brent? For instance, could I simply use a for-loop algorithm to obtain the induction factors?

Kind regards,
Wesley
Mon May 08, 2017 9:14 pm
Forum: Tidal Current
Topic: Aerodyn: Some input parameters for unsteady aerodynamic case
Replies: 3
Views: 6193

### Re: Aerodyn: Some input parameters for unsteady aerodynamic case

Sir,

Where could I get data for pitching moment coefficient (PMC)?

For instance, in the Unsteady report (Phase VI), there's PMC data for Re > 750,000, as attached.
I'm wondering if there's PMC data for Re < 750,000 (e.g. Re = 300k, 500k and 650k).

Kind regards,
Wesley
Wed Apr 26, 2017 11:29 pm
Forum: Computer-Aided Engineering Software Tools
Topic: How to link AeroDyn with structural code?
Replies: 5
Views: 1500

### Re: How to link AeroDyn with structural code?

Sir, Good day! Sir, I also have issues concerning coupling. From the matrix form of M[d^2x/dt^2] + C[dx/dt] + K[x] = F where F covers aerodynamic, centrifugal and gravitational forces, what would be the form of "F" looks like? For instance, in some general vibration texts, F is sometimes e...
Tue Apr 18, 2017 2:54 am
Forum: Computer-Aided Engineering Software Tools
Topic: Damping of the rotor blades
Replies: 14
Views: 8621

### Re: Damping of the rotor blades

Dear Lorenzo, Damping in the rotor comes from aerodynamics, dynamics (gyroscopic / coriolis, etc.), and structural (natural damping in a material due to friction). The first two are intrinsicly included in FAST. The last term--the structural damping--is specified as an input in FAST. The blade stru...
Tue Feb 28, 2017 6:09 am
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 14789

### Re: Help about BEM and NREL's Phase VI

Sir, Good day! Sir, I'm using trapezoidal rule in the computation of Tangential Force/Torque/Power. The formula requires indicating segments (i.e. distance between two radial positions, r(n+1)-r(n)). My computation started with r=1.257m (since this is the section where s809 is utilized). Sir, if I w...
Wed Jan 18, 2017 7:13 am
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 14789

### Re: Help about BEM and NREL's Phase VI

Jason.Jonkman wrote:Dear Wesley,

Regarding the limiting values at the tip, "yes," that is correct.

There are different methods to solve the BEM equations. Newton iterations are one method. In AeroDyn v15, we use Brent's method.

Best regards,

I see,
thanks sir!

Kind regards,
Wesley
Fri Jan 13, 2017 7:14 am
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 14789

### Re: Help about BEM and NREL's Phase VI

Dear Wesley, I'm assuming this Excel file you are referring to has your own implementation of BEM? When looking at the limit of the BEM solution with the Prandtl tip-loss model as r --> R at the tip, I would expect that a --> 1 and a' --> 0, which is what we have implemented in AeroDyn v15. (AeroDy...
Fri Jan 13, 2017 12:13 am
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 14789

### Re: Help about BEM and NREL's Phase VI

Sir, I'm doing BEM using Excel for initial testing. I notice for the blade element at the tip (i.e. r=R), the axial and tangential induction factor becomes 1 and -1 after the first run. This becomes a problem when the second run starts as the Relative Velocity at that element is zero. Any idea about...
Mon Dec 05, 2016 9:16 am
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 14789

### Re: Help about BEM and NREL's Phase VI

I see, thanks sir. My data got closer to the computed power, however variation exists in cn, ct. Sir, concerning the formula for cn, ct= are they in terms of inflow angle or angle of attack? btw, sir, regarding structural modelling,any idea how's proportional modelling approached? :) Kind regards, W...
Thu Dec 01, 2016 10:48 pm
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 14789

### Re: Help about BEM and NREL's Phase VI

Sir, Good day! Sir, if I'll use NREL Phase VI for aerodynamic validation, could I use cn, ct as the parameters of comparison for my BEM code? I've seen a tabulated data about this (i.e. Jonkman, 2003), though I have some reservation upon reading that these data (cl, cd, wind speed, aoa, cn, ct) refl...
Fri Sep 02, 2016 5:21 am
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 14789

### Re: Help about BEM and NREL's Phase VI

Sir, thanks for the file that you provided. I checked it and observed that the data concerning structural properties covers the radius until 5m only.

I'm using the r= 5.029m.

any idea about this one sir? should I extrapolate for instance to get the data @ 5.029m?
Thu Sep 01, 2016 10:51 am
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 14789

### Re: Help about BEM and NREL's Phase VI

Sir,

one question - are there any torsional stiffness/rigidity data concerning NREL Phase VI similar to this?

kind regards,
Wesley
Tue Aug 16, 2016 9:27 pm
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 14789

### Re: Help about BEM and NREL's Phase VI

Jason.Jonkman wrote:Dear Wesley,

Are you asking about real physical data? The blade deflections were not measured in UAE Phase VI experiments.

Best regards,

Yes sir.
The real physical data will be used for my aeroelastic validation using NREL's Phase VI.
Any suggestions sir?