Fluid kinematics around two circular cylinders moving towards impact
  The scale factors of an arbitrary orthogonal space are a measure of its content of homogeneous orthogonal space. In the present study, it is shown, that their spatial and temporal rates of variation do not contribute to the differential calculus of arbitrary functions in orthogonal space. Based on this, the Navier-Stokes equations are formulated accordingly, to provide a method of studying the kinematics of fluid motion in orthogonal plane space. Employing this formulation and regular perturbation theory, the kinematic physical measures of the flow of an incompressible, viscous fluid around two identical circular cylinders, which move with equal and opposite velocity towards central impact are evaluated. For this case, the space is parametrised according to the bipolar transformation of the cartesian plane. 
Nektarios Bampalas
physics.flu-dyn