Nonlinear waves in dry and wet Hertzian granular chains

Job S.; Santibanez F.; Tapia, F; Melo F.

Abstract

A one-dimensional dry granular medium, a chain of beads which interact via the nonlinear Hertz potential, exhibits strongly nonlinear behaviors. When such an alignment further contains some fluid in the interstices between grains, it may exhibit new interesting features. We report some recent experiments, analysis and numerical simulations concerning nonlinear wave propagation in dry and wet chains of spheres. We consider first a monodisperse chain as a reference case. We then analyze how the pulse characteristics are modified in the presence of an interstitial viscous fluid. The fluid not only induces dissipation but also strongly affect the intergrain stiffness: in a wet chain, wave speed is enhanced and pulses are shorter. Simple experiments performed with a single sphere colliding a wall covered by a thin film of fluid confirm these observations. We demonstrate that even a very small amount of fluid can overcome the Hertzian potential and is responsible for a large increase of contact stiffness. Possible mechanisms for wet contact hardening are related to large fluid shear rate during fast elastohydrodynamic collision between grains. © 2008 Elsevier B.V. All rights reserved.

Más información

Título según WOS: Nonlinear waves in dry and wet Hertzian granular chains
Título según SCOPUS: Nonlinear waves in dry and wet Hertzian granular chains
Título de la Revista: ULTRASONICS
Volumen: 48
Número: 06-jul
Editorial: Elsevier
Fecha de publicación: 2008
Página de inicio: 506
Página final: 514
Idioma: English
URL: http://linkinghub.elsevier.com/retrieve/pii/S0041624X08000401
DOI:

10.1016/j.ultras.2008.03.006

Notas: ISI, SCOPUS