Calibration of equations of state and design of high-pressure shock wave experiments using numerical simulation.

摘要

The equation of state (EOS) provides a closure condition for the equations of hydrodynamics. Several analytic forms of EOSs are given in the literature but they often do not fit existing shock Hugoniot data over a wide range of pressures. Furthermore, we would like to design high-pressure shock wave experiments to obtain more data. This prompts us to ask the following three questions: How can one calibrate an analytic EOS to existing data? Which EOS performs the best for a given material? How can one design high-pressure EOS experiments using a hydrodynamic simulation code?; The calibration of EOSs is accomplished through the use of nonlinear least-squares fits. The theoretical background and fitting procedure for several EOSs are discussed.; High-pressure EOS experiments are designed by using shock waves in convergent geometries. In order to gain confidence that simulations provide adequate experimental design, a one and two-dimensional hydrocode was verified and validated. The hydrocode produced reasonable results, but certain algorithmic shortcomings placed limits on accuracy and efficiency.