We derive computable a posteriori error estimates for the lowest order nonconforming Crouzeix-Raviart element applied to the approximation of incompressible Stokes flow. The estimator provides an explicit upper bound that is free of any unknown constants, provided that a reasonable lower bound for the inf-sup constant of the underlying problem is available. In addition, it is shown that the estimator provides an equivalent lower bound on the error up to a generic constant.
- posteriori error
- Crouzeix-Raviart element
- Stokes flow
Dörfler, W., & Ainsworth, M. (2005). Reliable a posteriori error control for non-conforming finite element approximation of Stokes flow. Mathematics of Computation, 74(252), 1599-1619. https://doi.org/10.1090/S0025-5718-05-01743-6