  A four-way coupling scheme for the direct numerical simulation of
particle-laden flows is developed and analyzed. It employs a novel adaptive
multi-relaxation time lattice Boltzmann method to simulate the fluid phase
efficiently. The momentum exchange method is used to couple the fluid and the
particulate phase. The particle interactions in normal and tangential direction
are accounted for by a discrete element method using linear contact forces. All
parameters of the scheme are studied and evaluated in detail and precise
guidelines for their choice are developed. The development is based on several
carefully selected calibration and validation tests of increasing physical
complexity. It is found that a well-calibrated lubrication model is crucial to
obtain the correct trajectories of a sphere colliding with a plane wall in a
viscous fluid. For adequately resolving the collision dynamics it is found that
the collision time must be stretched appropriately. The complete set of tests
establishes a validation pipeline that can be universally applied to other
fluid-particle coupling schemes providing a systematic methodology that can
guide future developments.
