Faraday waves in gas-fluidized beds subject to combined vertical and horizontal vibration

The dynamics of Faraday waves in a gas-fluidized bed vibrated in both the vertical and horizontal directions simultaneously were investigated using two-fluid model (TFM) simulations. Prior experimental and numerical studies have demonstrated the formation of Faraday waves in gas-fluidized beds, and the TFM simulations here are validated against prior experimental studies. The novelty of this study is subjecting a gas-fluidized bed to combined vertical and horizontal vibrations. The key physical insights are that (1) Faraday waves can still form when horizontal vibration is added and (2) the horizontal mixing rate and extent increases markedly by adding horizontal vibration. Further, non-dimensional empirical correlations and regime maps for wavelength and wave height were established based on dimensional analysis. Increasing vertical vibration frequency decreased horizontal mixing, yet increasing horizontal vibration frequency increased horizontal mixing. Increasing gas flow rate increased the rate of vertical mixing, but decreased the rate of horizontal mixing.