垂直振动激发下颗粒物质的能量耗散

本文对垂直振动激发下的铜和玻璃珠两种密集颗粒样品,通过实时测量样品盒的加速度和振台对它的作用力,研究了样品的平均耗散功率.实验发现该耗散功率在给定振动强度下随振动频率的变化曲线是一个峰值在几十赫兹的宽峰结构,在给定频率下随强度的变化具有幂率规律,其幂值小于简谐受迫振动模型的幂值2.这些结果将有助于研究测定颗粒流体和气体的迁移系数,以及它们在不同运动模式下的能耗差异.

Energy dissipation of a granular system under vertical vibration

For a vertically vibrating box filled with Cu grains or glass beads, we study power of dissipating energy of the granular system, by measuring acceleration of the box and force acting on it. It is found that for a given vibrating strength the power displays a wide peak structure centered at several tens Hz as vibrating frequency varies, and for a given frequency its variation with the strength obeys a power law, with an exponent smaller than that of a forced harmonic oscillator model 2. The results are considered to be useful for determining magnitudes of transport coefficients of granular liquids and gases, as well as difference in dissipative energy between their different dynamic patterns.