Kamerling Onnes Lab, Universiteit Leiden, Postbus 9504, 2300 RA Leiden, The Netherlands.
Phys Rev Lett. 2013 Nov 22;111(21):218003. doi: 10.1103/PhysRevLett.111.218003.
We experimentally probe nonlinear wave propagation in weakly compressed granular media and observe a crossover from quasilinear sound waves at low impact to shock waves at high impact. We show that this crossover impact grows with the confining pressure P0, whereas the shock wave speed is independent of P0-two hallmarks of granular shocks predicted recently. The shocks exhibit surprising power law attenuation, which we model with a logarithmic law implying that shock dissipation is weak and qualitatively different from other granular dissipation mechanisms. We show that elastic and potential energy balance in the leading part of the shocks.
我们通过实验研究了弱压缩颗粒介质中的非线性波传播，并观察到了从低冲击下的准线性声波到高冲击下的冲击波的转变。我们表明，这种转变冲击随着约束压力 P0 的增加而增大，而冲击波速度与 P0 无关——这是最近预测的颗粒冲击的两个特征。这些冲击波表现出令人惊讶的幂律衰减，我们用对数定律对其进行建模，这意味着冲击波的耗散较弱，与其他颗粒耗散机制在质上不同。我们表明，在冲击波的前沿部分，弹性和势能是平衡的。
