COMPUTATIONAL EFFICIENCY AND QUALITY OF DIFFERENT VERSIONS OF DISCONTINUOUS GALERKIN METHOD FOR LES/DES APPLICATIONS

摘要

Dual time stepping (DTS) time integrationtechniques for Discontinuous Galerkin (DG)method are presented for one-dimensionalBurgers equation and for full three-dimensionalNavier–Stokes equation system. Unfiltered andspatially filtered equations with Smagorinskysubgrid scale model are considered which arecompared in terms of energy spectrumresolution capability. Presented time integrationtechniques are applicable to unsteady largeeddy simulation problems and are designed tobe unconditionally stable in viscous regions ofthe flow. Computational efficiency of different(1–4) temporal order DTS techniques iscompared to the efficiency of the explicit DGscheme in two test cases. All computations areperformed with constant global physical timestep. High order spatial and temporaldiscretizations as well as implicit first orderpseudo-time scheme are described in details.