How does velocity sampling for OpenFAST coupled ALM work in AMR-Wind?

[LutzRohlfing]

Hi,

i have a question about how the AMR-Winds velocity sampling for the OpenFAST coupled ALM works. I read this paper: https://doi.org/10.1002/we.2965, detailing different sampling methods for velocity and their advantages and disadvantages. In the paper three options where presented:

1. sampling the velocity for the airfoil data on points on the centerline
2. sampling in a volume around the centerline
3. sampling on a line (ring) around the airfoils centerline

Which methodology does AMR-Wind use? Maybe also a different 4th option? In the paper also the relation of these sampling methods to smearing width epsilon and time step was investigated.