Wind Factors to Wind Velocity

#1

Hi @TheodorosGalanos,
In the windFile, what do you exactly do with all the wind factors for 36 directions?

Following is mentioned in the paper

These WF were used in combination with the TMY data to derive hourly wind velocities withing the area of interest.

Can you please be specific?

Do you take average of the WF for all the directions and then multiply the TMY wind velocities with that number and then write that number in the rows of the windFile?

No. You are using these WF for different directions. So when wind is coming from angle 0, the WF for that direction is used and then value of that WF * TMY wind velocity is written to the wind file. Is that correct?

#2

Hi Devang, yes WF are used for each different wind direction.

What happens is simple. You take a wind velocity plane of your area of interest. Then inside Paraview (ideally) you create a calculator filter and simply divide the wind velocity in the plane by the inlet wind velocity of your case. That gives you a WF for each point in the area of interest.

We then take these WFs and we multiply them with the wind velocity value, only for that direction, in the weather file. So the WF for 90 degrees is multiplied with WV values during all hours with 90 degrees wind in the weather file. Doing that for each direction you run the case for generates yearly wind value schedules.

I really should upload those files in hydrashare now the method and components are more stable.

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#3

Thanks a lot for confirming and elaborating @TheodorosGalanos!

#4

Hi @TheodorosGalanos,
I was wondering the same question as @devang. Thanks for answering.

I really should upload those files in hydrashare now the method and components are more stable.

Will be cool!!
-A.

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#5

Hello @TheodorosGalanos
I’ve tried to follow along with the work you and @chris have already done and elaborated. Just need some help about how to calculate the Velocity and WF in Paraview. I tried to import the .foam file into Paraview, exported into a .csv file, yet just got the u0, u1, and u2 components for velocity, differently from the one @chris already shared before “WindFactor_1.75m0” . So standing from me not a good user of Paraview, could you provide me with the equations in Paraview to calculate the wind speed at 1.1m (as recently recommended) and then get the WF. Thanks in advance.
Cheers,
Yasser

#6

So I’m sorry for disturbing, yet I guess I’ve found that over CFD-online. You use the equation U=sqrt(U_X^2+U_Y^2+U_Z^2) to get the magnitude (Velocity), then devide by the initial wind speed input for the Butterfly_Wind Vector component. I tried that and I think it worked with me to create two new arrays with the Velocity and WindFactors. Am I right?

#7

Hi Yasser,

That is correct, that’s how you calculate scalar velocity and WF. There is also a short cut to that in Paraview by using mag(U) before exporting.

Regards,
Theodore.

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#8

Many thanks @TheodorosGalanos