code: def flow_transition(Diam, Nu):
      
      #Checking input validity
      ut.check_range([Diam, ">0", "Diameter"], [Nu, ">0", "Nu"])
      return np.pi * Diam * RE_TRANSITION_PIPE * Nu / 4
docs: Return the flow rate for the laminar/turbulent transition.
  
      This equation is used in some of the other equations for flow.