Efficient simulations of shock-induced ignition in turbulent flows with a hybrid scheme

This study presents efficient simulations of shock-induced ignition in turbulent flows using a hybrid fifth-order weighted essentially non-oscillatory (WENO5) and sixth-order central difference (CD6) scheme (WENO5-CD6), coupled with a novel semi-coupled fourth-order Runge-Kutta (SC-RK4) integrator. The hybrid WENO5-CD6 scheme ensures efficient and accurate capture of both shock waves and broadband turbulent structures by employing sensors to adaptively combine CD6 for smooth regions and WENO5 for discontinuities. The SC-RK4 integrator addresses the challenges of stiff chemical reactions, outperforming traditional Strang splitting methods in near-limit combustion phenomena. The proposed methods are validated against homogeneous reactor and one-dimensional shock-induced ignition benchmarks, showing improved accuracy and efficiency. Simulations of reactive homogeneous isotropic turbulence reveal that increasing turbulent Mach numbers shortens ignition delay due to the pressure-gain effect induced by shocklets. In shock-turbulence interaction cases, the combustion regime transitions from partially to fully premixed flames, with autoignition and flame propagation modes coexisting before transitioning into a broken reaction zone dominated by distributed premixed flame elements. The results highlight the effectiveness of the WENO5-CD6 scheme in reducing computational cost while maintaining accuracy. Moreover, these findings provide insights into the effects of compressible turbulence on ignition delay and reaction wave propagation.