Coordinate cilindriche

$$\begin{array}{rcl} \nabla^2\ \vec{V} & = & \left(\ensuremath... ...z \ensuremath{\frac{\partial^2 u_z}{\partial z^2}} \end{array}$$

$$\begin{array}{rcl} & = & \vec{\imath}_r\ensuremath{\frac{\pa... ..._z \ensuremath{\frac{\partial^2 u_z}{\partial z^2}} \end{array}$$

$$\begin{array}{rcl} & = & \vec{\imath}_r \left( \ensuremath{... ...emath{\frac{\partial^2 u_z}{\partial z^2}} \right) \end{array}$$

$$\nabla^2\ \vec{V} = \vec{\imath}_r \left( \nabla^2 u_r - \frac{u_... ...tial u_r}{\partial z}} \right) +\vec{\imath}_\theta \left( \nabla^2 u_z \right)$$ (A.1)