Conceptual

A Priori Error Rates for Fully-Discrete Finite Elements of the Unsteady p(.,.)-Stokes Equations

How to prove convergence rates for a numerical scheme that solves a non-Newtonian incompressible flow whose power-law exponent varies in space and time: discretize with backward Euler in time and inf-sup-stable finite elements in space, then bound the velocity error under fractional regularity of the velocity and pressure. Students learn why a variable exponent complicates the analysis and how numerical experiments confirm the rates are optimal for exponents at least two.