Nonlinear Sound Propagation in Granular Media (SOUND)
research area: materials science
Nonlinear Sound Propagation in Granular Media
experiment acronym: SOUND
funding agency: ESA
grant number: ESA - Program
DLR - Institute for Materials Physics in Space, Cologne, Germany
Institut Langevin, ESPCI, Paris, France
Prof. Dr. Andreas Meyer, Dr. Matthias Sperl, Dr. Peidong Yu
Prof. Xiaoping Jia, Dr. Siet van den Wildenberg
Sound propagation in granular systems is a complex wave phenomena (e.g., multiple sound scattering, nonlinear acoustics), but also it may be used as a non-invasive tool to probe the packing structure and the mechanical properties [1-2]. Under weak compression and relatively strong excitation, the nonlinear nature of particle interaction becomes very important and is reflected by a transition of the propagation regime. Numerical simulation showed that the wave speed increases with the excitation amplitude according to a power law dependence . This dependence is a trademark of the soliton-like shock wave in the highly nonlinear regime and was later partially verified by ground experiments . The current limitation of such experiments is that the weight of the particles always causes some compression of the system, and a marginal or unjammed state proposed in  can not be reached for three-dimensional systems. Low gravity condition in this case becomes essential to realize this highly nonlinear regime. Therefore we propose building a nonlinear sound excitation and detection setup for low gravity facilities to fully investigate the wave speed and the dissipation under close-to-zero compression.
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-  L. R. Gomez, A. M. Turner, M. van Hecke, and V. Vitelli, "Shocks near Jamming", Phys. Rev. Lett., vol. 108, pp. 058001, Jan. 2012.
-  S. van den Wildenberg, R. van Loo, and M. van Hecke, "Shock waves in weakly compressed granular media", Phys. Rev. Lett. 111, 218003, Nov. 2013
experiment year: 2015
number of catapult launches: 2
number of drops: 6
experiment year: 2014
number of catapult launches: 8