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Efficiency and accuracy of time-accurate turbulent Navier-Stokes computations

1995; Linguagem: Inglês

10.2514/6.1995-1835

Christopher L. Rumsey, Mark D. Sanetrik, Robert T. Biedron, N. Duane Melson, Edward B. Parlette,

Advanced Numerical Methods in Computational Mathematics

The accuracy and efficiency of two types of subiterations in both explicit and implicit Navier-Stokes codes are explored for unsteady laminar circular-cylinder flow and unsteady turbulent flow over an 18-percent-thick circular-arc (biconvex) airfoil. Grid and time-step studies are used to assess the numerical accuracy of the methods. Nonsubiterative time-stepping schemes and schemes with physical time subiterations are subject to time-step limitations in practice that are removed by pseudo time sub-iterations. Computations for the circular-arc airfoil indicate that a one-equation turbulence model predicts the unsteady separated flow better than an algebraic turbulence model; also, the hysteresis with Mach number of the self-excited unsteadiness due to shock and boundary-layer separation is well predicted.