NUMERICAL-SOLUTIONS OF 1-D UNSTEADY NEAR-CRITICAL FLUID-FLOWS USING FINITE-VOLUME METHODS

This paper presents a number of algorithms using a finite volume metho d for solving the one-dimensional unsteady, low mach number hypercompr essible Navier-Stokes equations. Calculations are made, using the SIMP LE, SIMPLER and PISO algorithms, for fluids near their critical point which exhibit singularities in some of the physical properties. Of the se the most important are the isothermal compressibility, which goes t o infinity whereas the thermal diffusivity goes to zero. The numerical calculations are compared to analytical results, The numerical method gives an almost perfect description of acoustic saturation where the compressibility may be six or seven orders of magnitude greater than t hat of a perfect gas.