An efficient high-order compact scheme for the unsteady compressible Euler and Navier–Stokes equations
Résumé
Residual-Based Compact (RBC) schemes approximate the 3-D compressible Euler equations
with a 5th- or 7th-order accuracy on a 5 × 5 × 5-point stencil and capture shocks pretty
well without correction. For unsteady flows however, they require a costly algebra to
extract the time-derivative occurring at several places in the scheme. A new high-order
time formulation has been recently proposed [13] for simplifying the RBC schemes and
increasing their temporal accuracy. The present paper goes much further in this direction
and deeply reconsiders the method. An avatar of the RBC schemes is presented that greatly
reduces the computing time and the memory requirements while keeping the same type of
successful numerical dissipation. Two and three-dimensional linear stability are analyzed
and the method is extended to the 3-D compressible Navier–Stokes equations. The new
compact scheme is validated for several unsteady problems in two and three dimension. In
particular, an accurate DNS at moderate cost is presented for the evolution of the Taylor–
Green Vortex at Reynolds 1600 and Prandtl 0.71. The effects of the mesh size and of the
accuracy order in the approximation of Euler and viscous terms are discussed.
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