Uncoupled method for numerical simulation of the nonequilibrium flow in COIL

An uncoupled method was introduced to simulate numerically nonequilibrium flow which had the stiffness problem. Mixing reaction flows in COIL are simulated by solving the Reynolds averaged Navier-Stokes equations and species continuity equations. Equations are solved using four-stage Runge-Kutta time-stepping scheme on structured viscous mesh. The simulations are carried out with AUSM+up scheme. The method employs finite-rate chemistry and thermodynamic perfect gas properties for chemical reaction. The stiffness problem of chemical source is overcome by a semi-implicit method. The COIL numerical results are in good agreement with the results of AeroSoft's GASP^[8].