TLCD number question

[icnosvbovwb]

Dear @jjonkman


Q1:As you can see in the TLCD picture, can you tell me what a,b,c,d,e,f means?
Q2:Is the TLCD shown in the second picture only controlled by one TLCD? Or are there two TLCD controls?

[jjonkman]

Dear @icnosvbovwb,

Here are my responses:
Q1. The TLDC is defined by area rather than specific cross-sectional lengths. A = a*b (area_x or area_Y). A_ratio = c*d/a*b (area_ratio_X or area_ratio_Y). e and f are not explicitly defined, only L and B are defined.
Q2. Yes, there are two TLCD controls--one along X and one along Y.

Best regards,

[icnosvbovwb]

Dear @jjonkman

I just want to use TLCD to control the tower top displacement in the X direction. Is my setting correct?
But I see that by enabling/disabling the variable TMD degrees of freedom through the StC_ X_ DOF, StC_ Y_ DOF, and StC_ Z_ DOF to enable or disable TLCD, where the flag is (Used only when StC_ DOF_ MODE=1)，Does this have no effect on setting 3?

[jjonkman]

Dear @icnosvbovwb,

That is correct. The StC_X_DOF, StC_Y_DOF, and StC_Z_DOF flags are only used for the independent X-, Y-, or Z-direction TMDs (StC_DOF_MODE = 1); they are not used for the TLCDs.

I'm not too familiar with the TLCD option available in the StC module, but from what I can tell, when you enable TLCD (StC_DOF_MODE = 3), you'll get both a fore-aft (X) and side-to-side (Y) TLCD without the ability to disable either direction.

Best regards,

[icnosvbovwb]

Dear @jjonkman
Assuming that I only use TLCDs in the X direction instead of using TLCDs in the Y direction, can I keep the parameters in the Y direction very small, so that there is approximately no existence of TLCDs in the Y direction，right?

[jjonkman]

Dear @icnosvbovwb,

Again, I'm not an expert on TLCDs, but I would guess you want to set the Y-direction TLCD to have negligible mass and negligible motion by setting rho_Y to near zero and headLossCoeff_Y to a very high value.

Best regards,

[icnosvbovwb]

Dear @jjonkman


I applied TLCD on the top of the tower, and set rho_Y to near zero and headLossCoeff_Y to a very high value. From the results, there is still a control force in the Y direction. Can you tell me where this control force comes from?

[icnosvbovwb]

Dear @jjonkman


af10f2278.png)
As shown in the figure, can I determine one of the baffle opening sizes according to the table? Can I choose any one(A0/A) , right? Because I can't find the control parameter setting position of this baffle in the STC control file

[jjonkman]

Dear @icnosvbovwb,

The orifice is characterized by the head-loss coefficient inputs (headLossCoeff_X, headLossCoeff_Y) in the StC input file.

Best regards,

[icnosvbovwb]

Deae @jjonkman



I have roughly calculated the various parameters of the TLCD based on the tower top frequency of OC4, and placed the TLCD at a position of 77.6m, but the effect is not obvious. Can you provide some suggestions?

[jjonkman]

Dear @icnosvbovwb,

Again, I'm not an expert on TLCDs and can't comment on their design. Just a couple comments:

• To gain confidence in your use of the model, I would suggest trying to regenerate previously published results that used this model, such as those by Semyung Park of the University of Massachusetts-Amherst.
• I know the TMD model has been more widely used than the TLCC model, so, perhaps it is easiest of you design a nacelle-based damper with a TMD first, and then mimic that response with a TLCD-based damper.

Best regards,

[icnosvbovwb]

Dear @jjonkman


May I ask if TStC1_Fxi and TStC1_Fyi represents the control force in the X and Y directions of a TLCD? Or do they represent the control force of each of the two TLCDs? Is pitcure 1 correct or pitcure 2 correct?

[jjonkman]

Dear @icnosvbovwb,

The Structural Control (StC) outputs you refer to are the total forces in the X and Y coordinates in the inertial frame applied to the tower from the first tower-base StC; these forces include the contribution from both the X and Y TLCDs. So, neither of your pictures is correct.

Best regards,

[icnosvbovwb]

Dear @jjonkman
Thanks for your reply. I have another small question：can Fast.farm be run using Simulink?

[jjonkman]

Dear @icnosvbovwb,

NREL has not yet developed an interface between FAST.Farm and Simulink.

Best regards,

[icnosvbovwb]

Dear @jjonkman

Similarly, I set TLCD on the top of the tower and TMD in the Y direction on the platform, but I don't know where the force in the X direction on the platform comes from? The displacement of TMD in the X-direction of the platform is 0.

[jjonkman]

Dear @icnosvbovwb,

A TMD that moves only in the y direction can still cause a force in the x direction, that is, the force preventing the mass from moving in the x direction in the presence of other motions of the tower top. Presumably you tower top has some motion that results in TMD forces in the x direction.

Best regards,

[icnosvbovwb]

Dear @jjonkman


I only applied TLCD in the X direction on the top of the tower, and set rho_Y to near zero and headLossCoeff_Y to a very high value. From the results, there is still a control force in the Y direction. Similarly, The force preventing the TLCD from moving in the Y direction in the presence of other motions of the tower top. Right？

[jjonkman]

Dear @icnosvbovwb,

Yes, I agree with your interpretation.

Best regards,