Vortex Shedding: The Source of Noise and Vibration in Idling Circular Saws

Abstract

Vortices separating from the edges of cutting teeth were shown to be the dominant source of pressure fluctuation and hence noise in circular saws. Measurement of pressure on the surfaces of the blade and teeth showed: (1) strong periodicity of the pressure on the tooth lateral surfaces, (2) a 180 degree phase difference between the pressure variations on both tooth lateral surfaces, and (3) pressure variations dominantly occurring on the tooth surfaces rather than the blade surfaces. The presence of an afterbody, downstream of the blade and tooth edges of flow separation, was found necessary for significant aerodynamic excitation of the blade and generation of noise by the flow.