Robust a posteriori error estimates for subgrid stabilization of non-stationary convection dominated diffusive transport

We derive a robust residual a posteriori error estimator for time-dependent convection–diffusion–reaction problem, stabilized by subgrid viscosity in space and discretized by Crank–Nicolson scheme in time. The estimator yields upper bounds on the error which are global in space and time and lower bounds that are global in space and local in time. Numerical experiments illustrate the theoretical performance of the error estimator.