Editing Navier–Stokes equations (section)

===Pressure recovery===
Recovering pressure from the velocity field is easy. The discrete weak equation for the pressure gradient is,
<math display="block">(\mathbf{g}_i, \nabla p) = -\left(\mathbf{g}_i, \left(\mathbf{u}\cdot\nabla\right)\mathbf{u}_j\right) - \nu\left(\nabla\mathbf{g}_i: \nabla\mathbf{u}_j\right) + \left(\mathbf{g}_i, \mathbf{f}^I\right)</math>

where the test/weight functions are irrotational. Any conforming scalar finite element may be used. However, the pressure gradient field may also be of interest. In this case, one can use scalar Hermite elements for the pressure. For the test/weight functions <math display="inline">\mathbf{g}_i
</math> one would choose the irrotational vector elements obtained from the gradient of the pressure element.