Starting in the spring 2013, I videotaped the lectures for my MATH 676: Finite element methods in scientific computing course at the KAMU TV studio at Texas A&M. These are lectures on many aspects of scientific computing, software, and the practical aspects of the finite element method, as well as their implementation in the deal.II software library. Support for creating these videos was also provided by the National Science Foundation and the Computational Infrastructure in Geodynamics.

Note 1: In some of the videos, I demonstrate code or user interfaces. If you can't read the text, change the video quality by clicking on the "gear" symbol at the bottom right of the YouTube player.

Note 2: deal.II is an actively developed library, and in the course of this development we occasionally deprecate and remove functionality. In some cases, this implies that we also change tutorial programs, but the nature of videos is that this is not reflected in something that may have been recorded years ago. If in doubt, consult the current version of the tutorial.

Lecture 33.25: Which element to use. Part 2: Saddle-points problems

We use many different kinds of finite elements, depending on the equations we want to solve. For example, we may use the usual Lagrange elements for the Laplace equation, but we use Taylor-Hood elements for Stokes, Raviart-Thomas elements for the mixed Laplace, and Nedelec elements for the Maxwell equations. Then there is also a veritable zoo of the BDM, BDDM, ABW, ABF, Rannacher-Turek, Crouzeix-Raviart, and many other elements.

This second of two lectures discusses what elements one chooses for saddle point problems such as the Stokes or mixed Laplace equations, and what the rationale for these elements is.

Slides: click here