Sondergaard, R. and Chaney, K. and Brennen, C. E. (1990) Measurements of Solid Spheres Bouncing Off Flat Plates. Journal of Applied Mechanics, 112 (3). pp. 694-699. ISSN 0021-8936 http://resolver.caltech.edu/CaltechAUTHORS:SONjam90
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Recent years have seen a substantial increase of interest in the flows of granular materials whose rheology is dominated by the physical contact between particles and between particles and the containing walls. Considerable advances in the theoretical understanding of rapid granular material flows have been made by the application of the statistical methods of molecular gas dynamics (e.g., Jenkins and Savage (1983), Lun et al. (1984)) and by the use of computers simulations of these flows (e.g., Campbell and Brennen (1985), Walton (1984)). Experimental studies aimed at measurements of the fundamental rheology properties are much less numerous and are understandably limited by the great difficulties involved in trying to measure velocity profiles, solid fraction profiles, and fluctuating velocities within a flowing granular material. Nevertheless, it has become clear that one of the most severe problems encountered when trying to compare experimental data with the theoretical models is the uncertainty in the material properties governing particle/particle or particle/wall collisions. Many of the theoretical models and computer simulations assume a constant coefficient of restitution (and, in some cases, a coefficient of friction). The purpose of the present project was to provide some documentation for particle/wall collisions by means of a set of relatively simple experiments in which solid spheres of various diameters and materials were bounced off plates of various thickness and material. The objective was to provide the kind of information on individual particle/wall collisions needed for the theoretical rheological models and computer simulations of granular material flows: in particular, to help resolve some of the issues associated with the boundary condition at a solid wall. For discussion of the complex issues associated with dynamic elastic or inelastic impact, reference is made to Goldsmith (1960) and the recent text by Johnson (1985).
|Additional Information:||Contributed by the Applied Mechanics Division of the American Society of Mechanical Engineers for presentation at the Winter Annual Meeting, Dallas, Texas, Nov. 25-30, 1990. MECHANICS. Manuscript received by the ASME Applied Mechanics Division, Feb. 3, 1989; final revision, May 30, 1989. Paper No. 90-WA/APM-11. The authors wish to express their thanks to James Helgren who participated in setting up the experiments described here and to Hojin Ahn and Professors Knowles and Sabersky for their interest and encouragement.|
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|Deposited By:||Christopher Brennen|
|Deposited On:||08 Nov 2004|
|Last Modified:||26 Dec 2012 08:39|
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