Effect of gradation variation on particle transport process in a generalized flash food gully via CFD DEM method

Understanding the particle dynamics in flash food gullies can help us learn how particle systems work and how river landscapes evolve. While discrete particle-based simulation techniques can accurately capture the transient forces acting on individual particles and their movement trajectories, they also suffer from the problem of excessive computation. To assess the feasibility of applying simplified discrete particle simulation techniques, this paper examines the mechanics of particle transport with loose accumulation in a generalized main and branch gully with a right angle under three different particle gradations using a coupled computational fluid dynamics and discrete element method (CFD-DEM). Numerical results indicate that the accumulation formed by the single gradation particles sliding into the main gully has the greatest degree of encroachment on the gully space and influences the lifting of the water depth of the cross section the most, and its velocity peaks at the fastest speed after being swept away by the water flow. Comparing the cumulative mass and the particle transport rate of the main gully, this paper reveals the similarity in the particle transport process. Based on the number of particle gradation (n), the transport process of all particle gradations can be mutually converted using the time transformation scale n+1 n . This method can effectively unify the transport process of particles with different gradations. Given the result of the work presented in this paper, it can be taken as a reference for simplifying the calculation of particle transport simulation based on particles in flash food gullies.

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Opracowanie rekordu ze środków MNiSW, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2024).