code: def g_coil(FlowPlant, IDTube, RadiusCoil, Temp):
      
      return (g_straight(FlowPlant, IDTube).magnitude
              * (1 + 0.033 *
                  np.log10(dean_number(FlowPlant, IDTube, RadiusCoil, Temp)
                          ) ** 4
                 ) ** (1/2)
              )
docs: We need a reference for this.
  
      Karen's thesis likely has this equation and the reference.