# Tag Info

This maybe raises more questions than it answers, but here is what I think one should do. Lets assume that at the boundary point p, the velocity u is defined as $$u(p) = u_1 \phi_k(p) + u_2 \phi_{k+1} (p),$$ where $$\phi_k = \begin{bmatrix} \phi \\ 0 \end{bmatrix}, \quad \phi_{k+1} = \begin{bmatrix} 0 \\ \phi \end{bmatrix}$$ are corresponding nodal basis ...