Calculate unit normal vector on surface for a given position
\[\begin{split}\frac{\partial\Phi}{\partial\phi}(r,\phi,z)\times
\frac{\partial\Phi}{\partial z}(r,\phi,z)=
\begin{bmatrix}r\cos(\phi)\\r\sin(\phi)\\0\end{bmatrix}\end{split}\]
with radius \(r\), polar angle \(\phi\) and cylinder length
\(z\).
- Parameters:
- poslist
Position
- Returns:
- normallist
Normal vector