text: Given a uniform velocity of a fluid at any position in space:
  This flow is incompressible because the velocity is constant, the first derivatives of the velocity components are zero, and the total divergence is zero: 
  Given the circulation is always zero the flow is also irrotational, we can derive this from the Kelvin's circulation theorem and from the explicit computation of the vorticity:
  Being incompressible and two-dimensional, this flow is constructed from a stream function:
  from which
  and in cylindrical coordinates:
  from which
  As usual the stream function is defined up to a constant value which here we take as zero. We can also confirm that the flow is irrotational from:
  Being irrotational, the potential function is instead:
  and therefore
  and in cylindrical coordinates