Virtual Wind Tunnel

The Virtual Wind Tunnel

The Virtual Wind Tunnel module allows the user to calculate and cache multiple wind directions in a single calculation run. This module is forms the basis of most advanced modules including the Urban Comfort Mapping and EnergyPlus Airflow Network modules which both require that a virtual wind tunnel results directory exists.

  1. Set up a regular simpleFoam case however the user must ensure that the CFD domain has the following attributes:
    • Of equal lengths in the x and y directions (square in shape)
    • The model sits completely within the domain and will not have a sub-divided cell at the x and y boundaries after meshing with snappyHexMesh
    • Optional: To get a step size of at least 10 degrees ensure that the lengths along the x and y directions are a muliple of 9 times the base cell size
  2. Set an inlet velocity condition (ie. fixedVelocity or atmosBL) on the Max-Y boundary and a fixedPressureOutOnly on the Min-Y boundary
  3. Write the case files and mesh the domain as per a standard case
  4. In the ODS Studio Virtual Wind Tunnel menu:
    • Adjust the "Angular Step" variable until the step size (in degrees) as shown below is as desired
    • Set the "Initial Iterations" variable to the number of iterations that you would like to be carried out at the first angle (calculation of the 0-degree case)
    • Set the "Subsequent Iterations" variable to the number of iterations that you would like to be carried out for all subsequent wind directions
  5. Once the above is set up then press the "Run" button in the Virtual Wind Tunnel menu to start the calculation. Several new folders will be created for the calculation and upon completion a new folder labelled "VWT" will reside in the directory where your .blend file is saved. This "VWT" folder is a standard OpenFOAM case folder with except with time directories corresponding to calculated wind angles.

Refer to the video below for a demonstration of the virtual wind tunnel.