Calculate unit normal vector on surface for a given position
\[\begin{split}\frac{\partial\Phi}{\partial\phi}(\tilde r(z),\phi,z)\times
\frac{\partial\Phi}{\partial z}(\hat r(z),\phi,z)=
\begin{bmatrix}\tilde r(z)\cos(\phi)\\\tilde r(z)\sin(\phi)\\\tilde r(z)\hat r(z)\end{bmatrix}\end{split}\]
with polar angle \(\phi\) and radius functions along the \(z\)-axis
\[\begin{split}&\tilde r(z)=r_1+\frac{r_2-r_1}{l-1}(z-1)\\
&\hat r(z)=\frac{r_2-r_1}{l-1},\end{split}\]
with radii \(r_1\) and \(r_2\) and cone length \(l\).
- Parameters:
- poslist
Position
- Returns:
- normallist
Normal vector