A windshield wiper arm is provided on an outside of an aircraft and positioned to directly engage an air flow while the aircraft is traveling. The wiper arm includes an arm portion coupled to the aircraft and having an arm exterior surface, the arm portion extending along an arm axis and defining an arm length. A bead extends outwardly from the arm exterior surface and defines a bead exterior surface, the bead being sized sufficiently to engage a boundary layer of the air flow. A wiper blade is coupled to the arm portion. The bead prevents separation of the boundary layer from the arm exterior surface, thereby to attenuate shedding of vortices and associated vibrations and noise.