Requirements for Equation of State Table Interpolation

Due to the computational complexity of many wide-range equation of state models, tabulation is an essential tool allowing these models to be efficiently used in simulation codes. Tables record thermodynamic variables on either rectilinear or triangulated grids and then recover an equation of state model through interpolation of these points. Typically, codes have default interpolation methods that may be adjusted by users. Empiricism and intuition often govern the choice of methods. Using a one dimensional shock verification test, we investigate equation of state interpolation methods in Lagrangian and Eulerian hydrodynamic codes. Requirements and recommendations for interpolation order, consistency, continuity, and accuracy are examined through convergence studies with the analytic solution computed using an ideal gas equation of state. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.