Granular flows through vertical pipes controlled by an electric field.

摘要: The flow of granular nickel particles moving down vertical pipes from a hopper in the presence local, horizontal ac electric field is studied experimentally. initiated by opening bottom outlet pipe after fully filled with hopper. mass flowing out measured as function time an electronic balance. dependence steady-state rate Q, under each fixed voltage V, obtained. Depending on magnitude two types behaviors are observed. For low V ( V-c), no interface exists and whole region between electrodes densely filled; only one constant Q(A2) (The precise meaning Q(B) defined text.) rates for plotted V. monotonically decreasing which can be approximately fitted power law, exponent -0.8. while found to independent. These features result competition blocking effect electric-field gravity-driven pushing outlet. local able retard downward movement dense column existing above it, but ineffective doing so when dilute density.