docs: def turbulent_Martinelli(Re, Pr, fd):
      r'''Calculates internal convection Nusselt number for turbulent flows
      in pipe according to [2]_ as shown in [1]_.
  
      .. math::
          Nu  = \frac{RePr(f/8)^{0.5}}{5[Pr + \ln(1+5Pr) + 0.5\ln(Re(f/8)^{0.5}/60)]}
  
      Parameters
      ----------
      Re : float
          Reynolds number, [-]
      Pr : float
          Prandtl number, [-]
      fd : float
          Darcy friction factor [-]
  
      Returns
      -------
      Nu : float
          Nusselt number, [-]
  
      Notes
      -----
      No range is given for this equation. Liquid metals are probably its only
      applicability.
  
      Examples
      --------
      >>> turbulent_Martinelli(Re=1E5, Pr=100., fd=0.0185)
      887.1710686396347
  
      References
      ----------
      .. [1] Rohsenow, Warren and James Hartnett and Young Cho. Handbook of Heat
         Transfer, 3E. New York: McGraw-Hill, 1998.
      .. [2] Martinelli, R. C. (1947). "Heat transfer to molten metals".
         Trans. ASME, 69, 947-959.
      '''
      return Re*Pr*(fd/8.)**0.5/5/(Pr + log(1. + 5.*Pr) + 0.5*log(Re*(fd/8.)**0.5/60.))