Upwind scheme

Figure 169: Element participation for the Upwind Scheme
\begin{figure}\epsfig{file=figF5.eps,width=8cm}\end{figure}

In this simple scheme the facial value is set to the element center value upwind of the face. For instance for the flow in Figure 169:

$\displaystyle \overrightarrow{\phi}_e = \phi_P.$ (564)

The upwind scheme introduces spurious viscosity leading to smeared flow characteristics (unless a very fine mesh is used).