Adaptive Cartesian grid with mesh-less zones for compressible flow calculations

A hybrid grid method that combines the computational efficiency of adaptive Cartesian grids with the flexibility of mesh-less scheme is developed for calculation of compressible flows. The mesh-less zone is created around the geometry by producing layers of nodes along normal direction vectors. Last layer is used as virtual geometry for automatic generation of unstructured Cartesian grid around mesh-less zone. An efficient explicit central difference scheme with artificial dissipation terms and convergence acceleration techniques is developed for both Cartesian grid and mesh-less zones. The method is used for computation of inviscid and viscous flows around single and multi-element airfoils at transonic flow conditions. Results indicate good agreements with those of available unstructured finite-volume flow solver (Uns2D) and other reference numerical data. The new method is shown to reduce the computational cost up to 70% compared with the fully unstructured flow solver.

► A hybrid grid method is developed for calculation of compressible flows.
► The mesh-less zone is created around the geometry.
► The domain between this zone and outer boundary is filled by unstructured Cartesian grid.
► A unified explicit scheme is developed for both Cartesian grid and mesh-less zones.
► The method reduces the computational cost compared with the fully unstructured solver.