docs: def Nu_vertical_cylinder_Jakob_Linke_Morgan(Pr, Gr, turbulent=None):
      r'''Calculates Nusselt number for natural convection around a vertical
      isothermal cylinder according to the results of [1]_ correlated by [2]_, as
      presented in [3]_ and [4]_.
  
      .. math::
          Nu_H = 0.555 Ra_H^{0.25},\; 10^{4} < Ra < 10^{8}
  
          Nu_H = 0.129 Ra_H^{1/3},\; 10^{8} < Ra < 10^{12}
  
      Parameters
      ----------
      Pr : float
          Prandtl number [-]
      Gr : float
          Grashof number [-]
      turbulent : bool or None, optional
          Whether or not to force the correlation to return the turbulent
  		 result; will return the laminar regime if False; leave as None for
          automatic selection
  
      Returns
      -------
      Nu : float
          Nusselt number, [-]
  
      Notes
      -----
      Cylinder of diameter 3.5 cm, length from L/D = 4.3. Air as fluid.
      Transition between ranges is not smooth.
      If outside of range, no warning is given. Results are presented rounded in
      [4]_, and the second range is not shown in [3]_.
  
      Examples
      --------
      >>> Nu_vertical_cylinder_Jakob_Linke_Morgan(.7, 2E10)
      310.90835207860454
  
      References
      ----------
      .. [1] Jakob, M., and Linke, W., Warmeubergang beim Verdampfen von
         Flussigkeiten an senkrechten und waagerechten Flaschen, Phys. Z.,
         vol. 36, pp. 267-280, 1935.
      .. [2] Morgan, V.T., The Overall Convective Heat Transfer from Smooth
         Circular Cylinders, in Advances in Heat Transfer, eds. T.F. Irvin and
         J.P. Hartnett, V 11, 199-264, 1975.
      .. [3] Popiel, Czeslaw O. "Free Convection Heat Transfer from Vertical
         Slender Cylinders: A Review." Heat Transfer Engineering 29, no. 6
         (June 1, 2008): 521-36. doi:10.1080/01457630801891557.
      .. [4] Boetcher, Sandra K. S. "Natural Convection Heat Transfer From
         Vertical Cylinders." In Natural Convection from Circular Cylinders,
         23-42. Springer, 2014.
      '''
      Ra = Pr*Gr
      if turbulent or (Ra > 1E8 and turbulent is None):
          Nu = 0.129*Ra**(1/3.)
      else:
          Nu = 0.555*Ra**0.25
      return Nu