18 巻 (1981) 5 号 p. 301-310
The mechanism causing the generation of harmonic sound from singing sand into which a rod penetrates is investigated experimentally. Stick-slip behavior distinctly occurs on compression flow of the singing sand, which is the reason for generation of the harmonic sound. The stick-slip friction characteristic of a singing sand is measured with a penetration test for a packed bed of particles.
The relationship between material of the penetrating rod, the stick-slip friction characteristic of the singing sand and the nature of the sound from the singing sand are discussed. The mechanism by which the harmonic sound from the singing sand is generated be explained as fllows: When the rod is penetrated into a packed bed of the singing sand, the impulsive force of resistnce to penetration of the rod which occurs from the stick-slip friction acts on the penetrating rod. Therefore, longitudinal vibration of the rod is excited, and the harmonic sound is radiated to in atmosphere. The sound generation based on the friction of particles can be classified into a squeal noise and a rubbing noise related to the friction characteristic of the particles.