## Search found 12 matches

Sat Jul 04, 2020 8:09 am
Forum: Structural Analysis
Topic: Modeling of linear foundation for onshore turbine
Replies: 22
Views: 3321

### Re: Modeling of linear foundation for onshore turbine

Hi Drew, I just plain ignored these missing DOFs. In typical turbines they shouldn't make much of a difference. The biggest influence is probably that of the tower torsion. I didn't read the topic linked by you but I assume it suggests to emulate tower torsion with a yaw stiffness which should work ...
Mon Jun 08, 2020 7:45 am
Forum: Structural Analysis
Topic: Modeling of linear foundation for onshore turbine
Replies: 22
Views: 3321

### Re: Modeling of linear foundation for onshore turbine

And another question I received by mail: Q: The mass moment of inertia I1,I2 How you choose their values ? A: All masses, moments of inertia and stiffnesses I worked with came from a Bladed model. If you don't have such reference values, you might want to make the foundation like 10 times more inert...
Mon Jun 08, 2020 7:40 am
Forum: Structural Analysis
Topic: Modeling of linear foundation for onshore turbine
Replies: 22
Views: 3321

### Re: Modeling of linear foundation for onshore turbine

Here is another question and answer: Q: but how you choose the damping ratio as 0,0005 in some doc i found that they took as 0,15 ? why all the values of diag are 1 just 2 of them are different? (mass ans stiffness) .. A: 0.5% damping is quite usual. But 0.15% (or is it 15%?) may also work. You have...
Mon Jun 08, 2020 6:00 am
Forum: Structural Analysis
Topic: Modeling of linear foundation for onshore turbine
Replies: 22
Views: 3321

### Re: Modeling of linear foundation for onshore turbine

Hi meriem, I set the matrices as follows: - all matrices are diagonal because I didn't have more detailed data, but diagonal is usually a good choice in this case. - the damping matrix must be a real physical damping coefficient "d" (never mind the capital variable name in the script) but ...
Fri Jan 31, 2020 3:08 am
Forum: Structural Analysis
Topic: Modeling of linear foundation for onshore turbine
Replies: 22
Views: 3321

### Re: Modeling of linear foundation for onshore turbine

Here is my promised report. From what I saw so far it seems to work as expected. In the main fst file I set: 2 CompSub - Compute sub-structural dynamics (switch) {0=None; 1=SubDyn; 2=External Platform and "sub_file_path" SubFile - Name of file containing sub-structural input parameters (qu...
Mon Jan 27, 2020 11:58 pm
Forum: Rotor Aerodynamics
Topic: Unsteady Aerodynamics, Dynamic Stall and Dynamic Wake in AeroDyn 15
Replies: 2
Views: 1272

### Re: Unsteady Aerodynamics, Dynamic Stall and Dynamic Wake in AeroDyn 15

Great, thanks a lot!
Mon Jan 27, 2020 10:46 am
Forum: Rotor Aerodynamics
Topic: Unsteady Aerodynamics, Dynamic Stall and Dynamic Wake in AeroDyn 15
Replies: 2
Views: 1272

### Unsteady Aerodynamics, Dynamic Stall and Dynamic Wake in AeroDyn 15

Hi, when I get the warning "Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 1, Blade = 1", does that mean that only the dynamic stall feature is disabled for that blade and foil section or also the dynamic inflow/wake effect is turned off? I am asking, because I'm actu...
Tue Jan 21, 2020 6:19 am
Forum: Structural Analysis
Topic: Modeling of linear foundation for onshore turbine
Replies: 22
Views: 3321

### Re: Modeling of linear foundation for onshore turbine

Great, thanks I'll try this and report back how it works.
Tue Jan 21, 2020 6:16 am
Forum: Structural Analysis
Topic: Modeling of rotor imbalance with BeamDyn
Replies: 2
Views: 1105

### Re: Modeling of rotor imbalance with BeamDyn

Ahhh,
sorry, I didn't realize that the three individual BeamDyn files are in the main .fst file as opposed to ElastoDyn, where the induvidual blade properties are located inside the driver file.

 posted four minutes too late
Tue Jan 21, 2020 1:58 am
Forum: Structural Analysis
Topic: Modeling of rotor imbalance with BeamDyn
Replies: 2
Views: 1105

### Modeling of rotor imbalance with BeamDyn

Hi everyone, is there any way I can model a rotor mass imbalance when using BeamDyn for the blade dynamics? In ElastoDyn there are three individual files for the blade properties, so I can make one blade a bit heavier. But with BeamDyn there is only one file for all three blades, so all blades must ...
Tue Jan 21, 2020 1:47 am
Forum: Structural Analysis
Topic: Modeling of linear foundation for onshore turbine
Replies: 22
Views: 3321

### Re: Modelling of linear foundation

Hi Jason,
Indeed I am modeling an onshore turbine. I will edit the title accordingly.
Is the file format for the SubFile the same as when CompSub=1? Or is there any place I can find an example file (already looked in the matlab-toolbox and r-test repos)?

BR
Sun Jan 19, 2020 11:48 pm
Forum: Structural Analysis
Topic: Modeling of linear foundation for onshore turbine
Replies: 22
Views: 3321

### Modeling of linear foundation for onshore turbine

Hi everybody, I am trying to convert a model from Bladed to OpenFAST as accurate as possible. In Bladed the tower base can be either coupled to the inertial frame or to a specified mass/inertia via a single linear spring per DOF with specified stiffness. I would like to reproduce the later option wi...