Wind field file

Ashes can read .wnd files (Bladed format), typically used to represent a turbulent wind field and generated with TurbSim (see Turbulent Wind Creator).
In the folder TurbulentWind\Ashes to wnd, you will find the Python script Write_wnd_file.py. This script reads a file containing a wind field and writes it to a wnd file that can be then read by Ashes.

The format of the wind field is illustrated in the Wind_field_example.txt file.
This file has two sections:
Ashes wind field data contains general data about the wind field. The parameters available in this section are
  • Duration: the duration (in seconds) of the turbulent wind field
  • TimeStep: the time interval (in seconds) between two time steps
  • GridSize_Y: the number of grid points in the horizontal direction
  • GridSize_Z: the number of grid points in the vertical direction
  • ReferenceHeight: the height (in m) of the centre of the grid
  • GridSpacing_Y: the distance (in m) between two grid points in the horizontal direction
  • GridSpacing_Z: the distance (in m) between two grid points in the vertical direction
The second section contains the wind field.
Each line in this section specifies the wind particle velocity at a specific time and grid point. The first column indicates the time, while the second and third columns represent the point's location in the Y and Z directions of the grid, respectively. The last three columns contain the components of the wind particle velocity: the component perpendicular to the wind field, the horizontal component within the wind field, and the vertical component, respectively.

Coordinates (Y = 1, Z = 1) correspond to the gridpoint at the upper left corner.
The figure below illustrates the different parameters available:




Note: you have to make sure that the information given in the second section is consistent with the general field parameters, i.e. that the number of different time steps corresponds to the duration divided by the time step and that the number of lines for each time steps is equal to the number of grid points in Y multiplied by the number of grid points in Z.