On the flame stabilization of turbulent lifted hydrogen jet flames in heated coflows near the autoignition limit: A comparative DNS study

A numerical study of ignition and flame development characteristics in GCI combustion using large eddy simulations and chemical explosive mode analysis

“…For the ignition front, as shown in Figure 6(b), ϕ s < ϕ ω is seen in the throughout pre-ignition zone, which is consistent with previous research. 30,58 The lower limit of the crossover progress variable for all equivalence ratios, namely C = 0.48, can therefore be used to safely distinguished the deflagration regime at different equivalence ratios, as demonstrated in Figure 7. In the following sections, the conditional value α at C 0 = 0 . 48 will serve as the local flame propagation mode indicator.…”

Extension of the Spectral Difference Method to Combustion

“…Indeed, Dirichlet boundary conditions, which impose conservative variables directly at boundaries, make the problem ill-posed leading to unwanted behaviors or even instabilities. This is avoided by characteristic boundary conditions, widely employed in the context of FD [227] and FV [228], and also with more recent numerical methods such as DG [229], SD [117] and LBM [110]. Originally introduced by Thompson for hyperbolic systems of equations [230], they were extended to the non-reacting Navier-Stokes equations by Poinsot and Lele [231] who named them as Navier-Stokes Characteristic Boundary Conditions (NSCBC).…”