The removal of two attached particle pairs from a plane surface was studied. The computational fluid dynamics code FLUENT(TM) was used to evaluate the drag force and to simulate the flow field around the two attached spherical particles that are in contact with a plane subject to a shear flow. Critical shear rates for various vertically aligned particle-pair removal mechanisms from a plane surface are evaluated. The results show that rolling detachment is the dominant mechanism for removal of particle pairs from a plane surface, and the presence of fine surface roughness reduces the critical shear rate. It is also found that it is easier for a vertically aligned particle pair with the large particle on the top to be removed from the wall when compared with a pair with the large particle in contact with wall.