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Two-Phase Approach to Modeling the Grain-Fluid Flows with Deposition and Entrainment over Rugged Topography
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  • Hock-Kiet Wong,
  • Yih-Chin Tai,
  • Haruka Tsunetaka,
  • Norifumi Hotta
Hock-Kiet Wong
Department of Hydraulic and Ocean Engineering, National Cheng Kung University
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Yih-Chin Tai
Department of hydraulic and ocean engineering

Corresponding Author:yctai@mail.ncku.edu.tw

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Haruka Tsunetaka
Forestry and Forest Products Research Institute
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Norifumi Hotta
The University of Tokyo
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We present a grain-fluid mixture for debris flows moving on a rugged (non-trivial) topography, where entrainment and deposition may take place. The model equations are derived with respect to a terrain-following coordinate system, which is constructed based on the topographic surface. The coordinates are fixed in space, and a “subtopography” is added on the coordinate surface to account for the variation in the local topography when entrainment or deposition takes place. Numerical implementation is made based on a GPU-accelerated simulation tool, into which the entrainment-deposition mechanism is integrated accordingly. Two numerical examples are assigned to investigate the key features of the proposed model. One is on a horizontal plane, on which a finite mass of grain-fluid mixture is released from the state of rest. In this example, debris flow deposits significantly impact the post-event} morphology and the associated flow behaviors. The other concerns a moving mass down an inclined chute merging into a horizontal deposition plane, where the levee formation is reproduced. At the end, the model is validated against a debris flow experiment to evaluate its applicability.
05 May 2023Submitted to ESS Open Archive
05 May 2023Published in ESS Open Archive