Illustration of the data communication between different components. The point denoted by P is a centroid of the ghost cell of the component with blue grids and is also in the computation domain of an adjacent component with red grids. The point denoted by P is the centroid of the cell closest to P in the component with red grids. The reconstruction formulation of a variable is first calculated in the stencil centred on a cell with its centroid denoted by P′ in the component with red grids and then transferred to the ghost cell with its centroid denoted by P in the component with blue grids.