The Representation of Water Properties by Mathematical Splines

Cubic and bicubic piecewise polynomial splines are used to represent the boundaries between phases and the shapes of the phase surfaces in p(u, v), T(u, v), and v(p, h) diagrams. Good accuracy in the region of interest for pressurized water reactor applications is achieved at reasonable cost Furthermore, the continuity of the second derivatives of this method of interpolation results in smoother numerical behavior than does linear interpolation when implemented in computer programs solving differential equations.