Axel Coussement

Three-dimensional boundary conditions for numerical simulations of reactive compressible flows with complex thermochemistry

The Navier-Stokes characteristic boundary conditions (NSCBC) is a very efficient numerical strategy to treat boundary conditions in fully compressible solvers. The present work is an extension of the 3D-NSCBC method proposed by Yoo et al. and Lodato et al. in order to account for multi-component reactive flows with detailed chemistry and complex transport. A new approach is proposed for the outflow boundary conditions which enables clean exit of non-normal flows, and the specific treatment of all kinds of edges and corners is carefully addressed. The proposed methodology is successfully validated on various challenging multi-component reactive flow configurations.

Multicomponent real gas 3-D-NSCBC for direct numerical simulation of reactive compressible viscous flows

Abstract The topic of this paper is to propose an extension of the classical one-dimensional Navier–Stokes boundary conditions (1-D-NSCBC) for real gases initially developed by Okong’o and Bellan [1] to a 3-D-NSCBC formulation based on the work of Lodato et al. [2] and Coussement et al. [3] . All the differences due to the real gas formulation compared to the perfect gas formulation proposed in [3] are emphasized. A new way of determining the pressure relaxation coefficient is introduced for handling transcritical flows crossing the boundary. The real gas 3-D-NSCBC are then challenged on several test cases: a two-dimensional subsonic vortex convection, a subsonic supercritical bubble convection and a flame vortex interaction. All these test cases are performed by direct numerical simulation of multicomponent flows. It shows the stability of the boundary conditions without creating any numerical artifact.