Microscopic modeling of sound waves in granular material: Quarterly progress report, October 1, 1987-December 31, 1987

Technical Report · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5759657

Haff, P K

In previous work we have studied via computer simulation the transmission of elastic disturbances through a quasi-consolidated grain mass, as well as through a mass of particles undergoing shear deformation. In the past quarter we have been developing the capability of modifying our earlier quasi-consolidated studies, where periodic waves were generated by an oscillating boundary, in order to focus on the radiation of elastic energy from a single point down through a drain mass to a transducer at the bed. The oscillating boundary studies hinted at the importance of columnar structure in the grain fabric, but the lateral extent of the excitation transducer inhibited analysis of the role of individual grain columns. In the present work, a layer of grains is allowed to settle on a horizontal surface. A ''cooling'' algorithm is employed to speed the settling rate, which otherwise takes a substantial amount of computer time (more on this below). When the grains have come to rest, a sharply located pulse is injected at the surface of the bed, in the form of a downward impulse applied to a grain. The lowest layer of ''particles'' on the bed are monitored for the arrival of the wave resulting from the surface disturbance.

• Research Organization: California Inst. of Tech., Pasadena (USA)
• DOE Contract Number: FG22-86PC90959
• OSTI ID: 5759657
• Report Number(s): DOE/PC/90959-T4; ON: DE88000348
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010600* -- Coal
Lignite
& Peat-- Properties & Composition
COMPUTERIZED SIMULATION
DOCUMENT TYPES
GRANULAR MATERIALS
MATERIALS
PROGRESS REPORT
SIMULATION
SOUND WAVES
WAVE PROPAGATION