A comparative study of high-order variable-property segregated algorithms for unsteady low Mach number flows
In this paper, five different algorithms are presented for the simulation of low Mach flows with large temperature variations, based on second-order central-difference or fourth-order compact spatial discretization and a pressure projection-type method. A semi-implicit three-step Runge-Kutta/Crank-Nicolson or second-order iterative scheme is used for time integration. The different algorithms solve the coupled set of governing scalar equations in a decoupled segregate manner. In the first algorithm, a temperature equation is solved and density is calculated from the equation of state, while the second algorithm advances the density using the differential form of the equation of state. The third algorithm solves the continuity equation and the fourth algorithm solves both the continuity and enthalpy equation in conservative form. An iterative decoupled algorithm is also proposed, which allows the computation of the fully coupled solution. All five algorithms solve the momentum equation in conservative form and use a constantor variable-coefficient Poisson equation for the pressure. The efficiency of the fourth-order compact scheme and the performances of the decoupling algorithms are demonstrated in three flow problems with large temperature variations: non-Boussinesq natural convection, channel flow instability, flame-vortex interaction. Copyright (C) 2010 John Wiley & Sons, Ltd.
segregated algorithm low mach number large temperature variations variable density flows high-order compact schemes projection methods