COMPUTATION OF FLOWS WITH ARBITRARY EQUATIONS OF STATE

The extension of time-marching computations to fluids with arbitrary e quations of state is demonstrated by means of stability analyses, simp lified problems, and practical applications. Most of the examples use the properties of supercritical hydrogen for which the density varies by more than an order of magnitude for small changes in pressure and t emperature, but representative computations for incompressible fluids and perfect gases are also given to demonstrate the generality of the procedure. Because representative how velocities in typical supercriti cal fluids applications are much lower than the speed of sound, conver gence enhancement through eigenvalue control is often necessary. This is accomplished through a generalization of earlier preconditioning me thods that enables efficient computation of arbitrary equation of stat e fluids, perfect gases, and incompressible fluids by a single procedu re. The present approach thus provides a single method that is uniform ly applicable to all equations of state.