  The correct choice of interface conditions and effective parameters for
coupled macroscale free-flow and porous-medium models is crucial for a complete
mathematical description of the problem under consideration and for accurate
numerical simulation of applications. We consider single-fluid-phase systems
described by the Stokes-Darcy model. Different sets of coupling conditions for
this model are available. However, the choice of these conditions and effective
model parameters is often arbitrary. We use large scale lattice Boltzmann
simulations to validate coupling conditions by comparison of the macroscale
simulations against pore-scale resolved models. We analyse two settings (lid
driven cavity over a porous bed and infiltration problem) with different
geometrical configurations (channelised and staggered distributions of solid
grains) and different sets of interface conditions. Effective parameters for
the macroscale models are computed numerically for each geometrical
configuration. Numerical simulation results demonstrate the sensitivity of the
coupled Stokes-Darcy problem to the location of the sharp fluid-porous
interface, the effective model parameters and the interface conditions.
