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The force driving intruder particles to rise or sink in dense granular beds is shown to obey a general scaling law that is reminiscent of Archimedes' buoyancy, but with additional dependence on the intruder to bed particle size ratio. Predictions match observations of rise-sink behavior over a wide range of flow conditions in various numerical and experimental flow configurations.
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Jing et al. (2020) studied this question.
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