A new equation of motion is applied to bubbles and sand particles injected near the wall in a direct numerical simulation of a turbulent boundary layer of water. The surface-forces are considered systematically to assess their effect on particle motion, concentration, diffusion rates, and Lagrangian statistics. The results show that strong lift forces can be obtained when the particle's terminal velocity is aligned with the freestream direction but only small effects are obtained if the terminal velocity is directed away from the wall. While finite Reynolds number effects are found to be small for the quasi-steady drag force, the choice of history force model is quite sensitive-an effect attributed to the long "memory" of the creeping flow expression. In general, the Lagrangian statistics were found to be the most sensitive output, sometimes varying largely between choice of surface-forces.
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