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

1996; Elsevier BV; Volume: 25; Issue: 2 Linguagem: Inglês

10.1016/0045-7930(95)00043-7

1879-0747

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

Model Reduction and Neural Networks

The accuracy and efficiency of two different 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%-thick circular-arc (biconvex) airfoil. Grid and time-step studies are used to assess the numerical accuracy of the methods. For both explicit and implicit algorithms, nonsubiterative time-stepping schemes and schemes with physical time subiterations are subject to time-step limitations in practice that are removed by pseudo time subiterations (dual time stepping). 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.