docs: def laminar_entry_Seider_Tate(Re, Pr, L, Di, mu=None, mu_w=None):
      r'''Calculates average internal convection Nusselt number for laminar flows
      in pipe during the thermal entry region as developed in [1]_, also
      shown in [2]_.
  
      .. math::
          Nu_D=1.86\left(\frac{D}{L}Re_DPr\right)^{1/3}\left(\frac{\mu_b}
          {\mu_s}\right)^{0.14}
  
      Parameters
      ----------
      Re : float
          Reynolds number, [-]
      Pr : float
          Prandtl number, [-]
      L : float
          Length of pipe [m]
      Di : float
          Diameter of pipe [m]
      mu : float, optional
          Viscosity of fluid, [Pa*s]
      mu_w : float, optional
          Viscosity of fluid at wall temperature, [Pa*s]
  
      Returns
      -------
      Nu : float
          Nusselt number, [-]
  
      Notes
      -----
      Reynolds number should be less than 10000. This should be calculated
      using pipe diameter.
      Prandlt number should be no less than air and no more than liquid metals;
      0.7 < Pr <  16700
      Viscosities should be the bulk and surface properties; they are optional.
      Outside the boundaries, this equation is provides very false results.
  
      Examples
      --------
      >>> laminar_entry_Seider_Tate(Re=100000, Pr=1.1, L=5, Di=.5)
      41.366029684589265
  
      References
      ----------
      .. [1] Sieder, E. N., and G. E. Tate. "Heat Transfer and Pressure Drop of
         Liquids in Tubes." Industrial & Engineering Chemistry 28, no. 12
         (December 1, 1936): 1429-35. doi:10.1021/ie50324a027.
      .. [2] Serth, R. W., Process Heat Transfer: Principles,
         Applications and Rules of Thumb. 2E. Amsterdam: Academic Press, 2014.
      '''
      Nu = 1.86*(Di/L*Re*Pr)**(1/3.0)
      if mu_w and mu:
          Nu *= (mu/mu_w)**0.14
      return Nu