Searched for: subject%3A%22mixing%22
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Chavarrias Borras, V. (author), Arkesteijn, L. (author), Blom, A. (author)
The active layer model (Hirano, 1971) is frequently used for modeling mixed-size sediment river morphodynamic processes. It assumes that all the dynamics of the bed surface are captured by a homogeneous top layer that interacts with the flow. Although successful in reproducing a wide range of phenomena, it has two problems: (1) It may become...
journal article 2019
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Schielen, R.M.J. (author), Blom, A. (author)
We derive an idealized model of a gravel-sand river bifurcation and analyze its stability properties. The model requires nodal point relations that describe the ratio of the supply of gravel and sand to the two downstream branches. The model predicts changes in bed elevation and bed surface gravel content in the two bifurcates under...
journal article 2018
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Chavarrias Borras, V. (author), Stecca, G. (author), Blom, A. (author)
In this paper we analyze the Hirano active layer model used in mixed sediment river morphodynamics concerning its ill-posedness. Ill-posedness causes the solution to be unstable to short-wave perturbations. This implies that the solution presents spurious oscillations, the amplitude of which depends on the domain discretization. Ill-posedness...
journal article 2018
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Chavarrias Borras, V. (author), Blom, A. (author), Orru, C. (author), Martín-Vide, Juan Pedro (author), Viparelli, Enrica (author)
Laboratory experiments were conducted on a sand-gravel Gilbert delta to gain insight on its dynamics under varying base level. Base level rise results in intensified aggradation over the topset, as well as a decrease in topset slope and topset surface coarsening, the signals of which migrate in an upstream direction. Preferential deposition...
journal article 2018
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Blom, A. (author), Chavarrias Borras, V. (author), Ferguson, Robert I. (author), Viparelli, Enrica (author)
Downstream fining of bed sediment in alluvial rivers is usually gradual, but often an abrupt decrease in characteristic grain size occurs from about 10 to 1 mm, i.e., a gravel-sand transition (GST) or gravel front. Here we present an analytical model of GST migration that explicitly accounts for gravel and sand transport and deposition in the...
journal article 2017
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Blom, A. (author), Arkesteijn, L. (author), Chavarrias Borras, V. (author), Viparelli, Enrica (author)
journal article 2017
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Stecca, G. (author), Siviglia, Annunziato (author), Blom, A. (author)
We present an accurate numerical approximation to the Saint-Venant-Hirano model for mixed-sediment morphodynamics in one space dimension. Our solution procedure originates from the fully-unsteady matrix-vector formulation developed in [54]. The principal part of the problem is solved by an explicit Finite Volume upwind method of the path...
journal article 2016
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Stecca, G. (author), Siviglia, A. (author), Blom, A. (author)
Sediment of different size are transported in rivers under the action of flow. The first and still most popular sediment continuity model able to deal with mixed sediment is the so-called active layer model proposed by Hirano (1971, 1972). In this paper, we consider the one-dimensional hydromorphodynamic model given by the Saint-Venant equations...
journal article 2014
Searched for: subject%3A%22mixing%22
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