Using staggered grids with characteristic boundary conditions when solving compressible reactive Navier-Stokes equations

International audienceA specific (hybrid) arrangement of variables is discussed to solve reactive compressible Navier-Stokes equations on staggered-like grids with high-order finite difference schemes. The objective is to improve the numerical flow solution at boundaries. Hybrid arrangement behaviour is compared with 'pure' colocated and staggered strategies. Classical Fourier analysis shows accuracy to be significantly improved in the hybrid case. One-dimensional laminar flame test demonstrates increased robustness (in terms of mesh resolution), whereas computation of 1D exiting pressure wave propagation gives evidence that the method also improves accuracy in the prediction of non-reflecting outflows, compared e.g. with the fully staggered scheme of (J. Comput. Phy. 2003). Multidimensional extension is illustrated through turbulent 2D planar and 3D expanding flames simulations