Author(s): Michele Iervolino; Massimo Greco; Angelo Leopardi
Linked Author(s): Michele Iervolino, Massimo Greco
Keywords: Dam break; Mobile bed; Non-equilibrium model; Numerical model
Abstract: Simulation of dam-break induced waves over a mobile bed is an hard test for numerical models for both mathematical and physical modelling reasons. From a mathematical point of view capturing of wave front celerities requires adequate numerical schemes. About the physical aspects it is important to point up that the special features of the phenomenon lead to reject the hypothesis of immediate adaptation of solid transport to hydrodynamics. Experimental investigation has shown that the scouring wave evolves with timescales which are rather close to that of hydrodynamics, and the strong coupling between solid and liquid phase markedly weakens the hypothesis under which common morphodynamical models can be applied. Then non-equilibrium transport models are required. In the present work available literature data by different Authors are compared against numerical results obtained by a non-equilibrium lagrangian model. All tests are characterized by a dry bed downstream and are different for diameter and weight of the material. Very different behaviours are observed for light and heavy particles and this aspect greatly influences the hydrodynamics. Numerical results appear encouraging. The principal features of phenomenon are well reproduced and the agreement between simulations and data is good for the heavier particles experiments. Experiences with lighter material are characterized by global movement of the bed, that cannot be reproduced by purely hydrodynamical models. Results permit to affirm that the use of a non-equilibrium model improves reproduction of such kind of phenomena.