“…As shown in Fig. 2b, the two-grid approach is built on top of a staggered solution algorithm in which the flow and geomechanics subproblems are solved sequentially and iteratively using a fixed stress split iterative scheme [22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,21,46,47,48,49,50,51,52]. The accuracy of the two-grid method has been demonstrated for the classical Mandel's problem [53,54] in our earlier work [21].…”