make the following text clearer.
In the Upwind scheme we replace the value at the face with the value at the adjacent upstream node. For the flow to the right (Pe > 0) as shown in the diagram, we replace the values as follows ;
In the Upwind scheme we replace the value at the face with the value at the adjacent upstream node. For example, for the flow to the right (Pe > 0) as shown in the diagram, we replace the values as follows ;