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<p>Surges are dangerous phenomena that amplify the discharge and destructive potential of gravitational mass flows. The origin of surges is linked to a wide range of possible mechanisms that fuel instability. In this paper we present new methods of image analysis to investigate the onset of instabilities in steady dry granular flows. We apply these methods to shallow flows of rounded ceramic granules and four natural sands of varying grain size in vertically rotating drum of 2.46&#xa0;m diameter. Despite the constant imposed velocity boundary condition, surges were observed as sinusoidal variations in front displacement and velocity. For flows of increasing velocity, surges appear as a higher relative velocity that is independent of initial velocity. For the case investigated in detail here, surges always had 0.1 m/s higher velocity. Periodic instabilities were identifiable for all four sands, but no surges were detectible for the ceramic, indicating that idealized, lower friction and more collisional dry granular flows may be less prone to develop flow instabilities.</p> Graphical Abstract <p></p>

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Surge instability of dry granular materials in large scale rotating drum experiments

  • 期刊论文

  • 发表日期：

    2026年4月20日

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  • A. Fawley,
  • R. Kaitna,
  • W. Andy Take

摘要

Surges are dangerous phenomena that amplify the discharge and destructive potential of gravitational mass flows. The origin of surges is linked to a wide range of possible mechanisms that fuel instability. In this paper we present new methods of image analysis to investigate the onset of instabilities in steady dry granular flows. We apply these methods to shallow flows of rounded ceramic granules and four natural sands of varying grain size in vertically rotating drum of 2.46 m diameter. Despite the constant imposed velocity boundary condition, surges were observed as sinusoidal variations in front displacement and velocity. For flows of increasing velocity, surges appear as a higher relative velocity that is independent of initial velocity. For the case investigated in detail here, surges always had 0.1 m/s higher velocity. Periodic instabilities were identifiable for all four sands, but no surges were detectible for the ceramic, indicating that idealized, lower friction and more collisional dry granular flows may be less prone to develop flow instabilities.

Graphical Abstract