A priori error estimates of two monolithic schemes for Biot's consolidation model

This paper concentrates on a priori error estimates of two monolithic schemes for Biot's consolidation model based on the three-field formulation introduced by Oyarzua et al. (SIAM J Numer Anal, 2016). The spatial discretizations are based on the Taylor-Hood finite elements combined with Lagrange elements for the three primary variables. We employ two different schemes to discretize the time domain. One uses the backward Euler method, and the other applies the combination of the backward Euler and Crank-Nicolson methods. A priori error estimates show that both schemes are unconditionally convergent with optimal error orders. Detailed numerical experiments are presented to validate the theoretical analysis.