A single vortex is obtained in radio-frequency capacitive discharge in argon gas.The dust subsystem is confined in the horizontal plane with an asymmetrical saw structure placed on the lower electrode.The vortex rotates as a whole along the long side of the saw-teeth.Asymmetry of the saw structure plays an important role in the rotation of the vortex.Nonzero curl of the total force resulting from the local ion flow and the electric field in the plasma sheath could be attributed to the persistent rotation of vortex.