[NotDrJeff]

Hello,

I am using a regular hexahedral mesh for solving an atmospheric boundary layer flow. In order to achieve a "quasi-equilibrium" statistically steady state, I am using cyclic boundary conditions on the sides of my domain. However, to avoid the unrealistic "looping" of large coherent structures I am imposing a flow velocity at an angle to the domain (rather than normal to the boundaries) to help break up some of these structures.

Here is my issue. OpenFOAM calculates the velocity components parallel to the mesh. But for analysis, I am interested in the stream-wise and cross-stream velocity fields.

How can I generate these new velocity components? Is there a utility I can use? Do I need to write a functionObject? Something else?

I would like to do this for other vector fields as well.

Thank you!

[NotDrJeff]

Sorry, I should've done a bit more googling before posting here.

After posting, I found another thread that is similar. But I will leave this thread here in case someone else finds it helpful.

I think the solution to my problem was to add the following to my controlDict.

  transform
  {
   type    fieldCoordinateSystemTransform;
   libs    (fieldFunctionObjects);

   fields
   (
    qmean
    Rmean
    U
    Uprime
   );

   coordinateSystem
   {
    origin    (0 0 0);

    coordinateRotation
    {
     type    axisAngle;
     axis    (0 0 1);
     angle   30;
    }
   }
  }

If It doesn't work I'll post another reply.