The motion of clusters of particles at the wall of a circulating fluidized-bed (CFB) has been observed using a thermal-imaging technique for flow visualization. Dynamic properties of clusters adjacent to the wall were measured, including the residence time of the clusters at the wall and the velocities at which they travel. The properties were measured for variations in superficial gas velocity, external solids recirculation rate, density of the solid material, and average particle diameter. Average cluster velocities were measured in the range of 1.1-1.2 m s(-1), with little dependence seen on any of the operating conditions. Average cluster-wall contact times were measured in the range of 0.15-0.50 s, with some dependence on solid density observed. A simplified model for the motion of clusters near a wall has been developed, treating the clusters as permeable bodies traveling adjacent to a wall in a quiescent fluid. This model allows for the application of computational methods to study the flow in and around clusters, as well as the calculation of lift (normal to the wall) and drag (parallel to the wall) forces on the clusters. These simulations show the presence of a substantial drag force, which helps explain the magnitudes of the observed cluster velocities. The simulations also show the presence of a lift force, which can be used to predict the observed cluster-wall contact times. The agreement between the simulations and the measured contact times is an indication that the lifting force is the phenomenon governing the removal or shedding of clusters from the wall region.