We present an
a posteriori error estimation for the numerical solution of a stochastic
variational problem arising in the context of parametric uncertainties. The
discretization of the stochastic variational problem uses standard finite elements in
space and piecewise continuous orthogonal polynomials in the stochastic domain. The
a posteriori methodology is derived by measuring the error as the functional
difference between the continuous and discrete solutions. This functional difference is
approximated using the discrete solution of the primal stochastic problem and two
discrete adjoint solutions (on two imbricated spaces) of the associated dual stochastic
problem. The dual problem being linear, the error estimation results in a
limited computational overhead. With this error estimate, different adaptive
refinement strategies of the approximation space can be thought of: applied to the
spatial and/or stochastic approximations, by increasing the approximation
order or using a finer mesh. In order to investigate the efficiency of different
refinement strategies, various tests are performed on the uncertain Burgers’
equation. The lack of appropriate anisotropic error estimator is particularly
underlined.
Keywords
error analysis, stochastic finite element method,
uncertainty quantification, refinement scheme