A high-order numerical algorithm for DNS of low-Mach-number reactive flows with detailed chemistry and quasi-spectral accuracy

Emmanuel Motheau (1) , John Abraham (1, 2)

1 University of Adelaide
2 Purdue University [West Lafayette]

A novel and efficient algorithm is presented in this paper to deal with DNS of turbulent reacting flows under the low-Mach-number assumption, with detailed chemistry and a quasi-spectral accuracy. The temporal integration of the equations relies on an operating-split strategy, where chemical reactions are solved implicitly with a stiff solver and the convection-diffusion operators are solved with a Runge-Kutta-Chebyshev method. The spatial discretisation is performed with high-order compact schemes, and a FFT based constant-coefficient spectral solver is employed to solve a variable-coefficient Poisson equation. The numerical implementation takes advantage of the 2DECOMP&FFT libraries developed by Li and Laizet [1], which are based on a pencil decomposition method of the domain and are proven to be computationally very efficient. An enhanced pressure-correction method is proposed to speed-up the achievement of machine precision accuracy. It is demonstrated that a second-order accuracy is reached in time, while the spatial accuracy ranges from fourth-order to sixth-order depending on the set of imposed boundary conditions. The software developed to implement the present algorithm is called HOLOMAC, and its numerical efficiency opens the way to deal with DNS of reacting flows to understand complex turbulent and chemical phenomena in flames.

Mots clés: DNS; Low-Mach-number; Detailed chemistry; Turbulent reacting flow; High-order methods; Spectral accuracy; Operator splitting

Domaines: Mécanique des fluides [physics.class-ph]; Analyse numérique [math.NA]; Physique mathématique [math-ph]; Milieux fluides et réactifs

Emmanuel Motheau, John Abraham. A high-order numerical algorithm for DNS of low-Mach-number reactive flows with detailed chemistry and quasi-spectral accuracy. Journal of Computational Physics, 2016, 313, pp.430-454. ⟨10.1016/j.jcp.2016.02.059⟩. ⟨hal-01297033⟩