An improved uncoupled finite volume solver for simulating unsteady shock-induced combustion

Unsteady shock-induced combustion is highly complicated due to the interactive physics-chemistry phenomena which are multi-scales in space and time. Especially, rigidity or stiffness of the Ordinary Differential Equations (ODEs) including the temporal solutions of both the chemical source terms and the flow equations may introduce significant computational cost due to the tiny time-steps of explicit methods or the complicated Jacobian matrix of implicit methods. A modified uncoupled method, which follows the idea of Strang splitting and has proved to be simple and efficient for solving the reactive flow system, is applied with using unstructured finite volume discretization and detailed reaction mechanisms. In order to further improve the efficiency of the uncoupled method, a chemical reaction detection criterion is designed to adaptively turn off chemical reaction computation. Numerical tests have shown significant efficiency improvement and satisfactory accuracy of the presented method.