Rotation colouring of streamlines

Development
1

Hey all, does anyone know what the rotation colouring on streamlines actually represents? How does is relate to the vorticity and angular velocity? What is the equation ParaView uses to calculate the rotation?

Thanks,
Much appreciated
Jessie

2

vtkStreamTracer.cxx:308

//------------------------------------------------------------------------------
void vtkStreamTracer::CalculateVorticity(
  vtkGenericCell* cell, double pcoords[3], vtkDoubleArray* cellVectors, double vorticity[3])
{
  double* cellVel;
  double derivs[9];

  cellVel = cellVectors->GetPointer(0);
  cell->Derivatives(0, pcoords, cellVel, 3, derivs);
  vorticity[0] = derivs[7] - derivs[5];
  vorticity[1] = derivs[2] - derivs[6];
  vorticity[2] = derivs[3] - derivs[1];
}

Generally used for ribbons orientation.

3

Hey Mathieu,

I really appreciate the response, this is the vorticity though. I finally found what the rotation field is if anyone is interested; it’s the curvature of the streamlines. Thank you paraview, super useful.

Jessie

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