Wind driven rain rose

Hi to all,

I am trying to create a wind driven rain rose similar to those from WUFI to include as part of a climate analysis to identify the critical walls.

I have found this rather simple formula from WUFI forum:
The amount of driving rain is calculated according to our model as follows:

R_wdr = R_h * ( R1 + R2 * V_10 * cos(theta) )

R_wdr: Amount of Driving Rain
R_h: normal rain (on horizontal surface)
R1: driving rain coefficient (depends on inclination)
R2: driving rain coefficient (depending on wind velocity) V_10cos(theta))
V_10: velocity of wind 10m over ground
theta: angle between wind direction and surface normal

And this simplified method

But it does not specify if the wind velocity is the mean wind velocity per orientation or for every hour. I am assuming that should be for every hour since the wind direction against the walls varies for every hour. Some other documentation says average wind direction (ASHRAE 160), but this term is very confusing to me.
I would be grateful if you could bring some insight here.
So far this is my routine. Please let me know if I am doing something wrong.
Wind Driven Rain (46.2 KB)

I think I found out where my mistake was. I was mass adding the condition larger than (0,1), instead of culling the results.