When a corrugated pipe is swirled i

When a corrugated pipe is swirled it produces a musically interesting sound. By increasing its rotational speed one can produce a series of frequencies corresponding to the modes of the open-open pipe. An interesting issue, raised since the early studies on the whistling of corrugated pipes, is that the fundamental acoustic mode is not whistling. This aspect has been related in the literature to the onset of turbulence in the pipe flow. In the present paper we provide a critical literature review and a physical model for the sound production, which contradicts the explanation of the missing fundamental mode presented in the literature.收起