The effect of the action of shearing on the concentration field in a shear cell was investigated numerically. One cylindrical fluid column present in a capillary of a shear cell segment, 1 to 2 mm in diam and 4 to 10 mm long, was modeled. Here only Ga-doped Ge was used, and it was found that the shearing action disrupts the concentration field to a depth of about one capillary diameter from each sheared end. Ln this disrupted region, the concentration field was mixed to near uniformity. The convection generated by shearing rapidly dissipates and is effectively zero within 10 s after the end of shear. For shear cell segment capillary aspect ratios l/d greater than about 3, the central portion of the fluid column is expected to be unaffected by the shearing action.