Grid-projection schemes for approximation of the second order partial differential equations on irregular computational meshes

A family of grid-projection schemes was constructed for approximation of the second order partial differential equations with a variable coefficient in tensor form. The developed schemes have the property of conservatism and retain the property of self-adjointness inherent to the original differential operator. The proposed schemes are designed to perform calculations on three-dimensional irregular computational meshes, including tetrahedral meshes, mixed meshes (meshes of arbitrary polyhedra) and AMR (oc-tree type).