In this report we propose two highly efficient ensemble algorithms incorporating the gPAV and the rotational pressure correction methods for computing Stokes-Darcy flow ensembles. All variables are fully decoupled including the three components of the velocity, leading to smaller linear systems to be solved at each time step. Moreover, all ensemble members share the same constant coefficient matrix for which the fast block CG method can be applied for computing the ensemble at one pass at significantly reduced computational cost. We prove the two new ensemble algorithms are unconditionally sta...
