This paper shows the recent results obtained in the field of the numerical and experimental investigation on the dynamics of an underwater non-cohesive sediment deposit subjected to an impulsive forcing. The aim of this work is to provide the basis for the development of an innovative technique that could be applied to increase the effectiveness of sediment removal at the bottom of an artificial reservoir through the combined use of submerged explosions and flushing maneuvers. The first part of the paper deals with the early Smoothed Particle Hydrodynamics (SPH) 2D simulations of a gas explosion and interaction with heterogeneous media. Subsequently are illustrated the experimental tests concerning the injection of a cold CO2 jet from the bottom of a 2D laboratory tank containing water and a sand bed at initial rest condition: these experiments were carried out to provide a first insight in the physics of the water-sediment impulsive dynamics including some similarities with the underwater explosion inside a non-cohesive sediment layer at rest. Finally the experimental tests were simulated with the SPH method by introducing some severe approximations in order to handle heterogeneous materials. Both initial rest condition and flushing maneuver were investigated. Even if some improvements of the model are required, the results show good qualitative agreement with the experimental frames; the SPH model can therefore lead to a first evaluation of the scouring effect when the gas injection and flushing maneuvers are combined.
Experimental and numerical investigation on the impulsive dynamics of underwater non-cohesive sediment
MANENTI, SAURO;SIBILLA, STEFANO;GALLATI, MARIO;
2012-01-01
Abstract
This paper shows the recent results obtained in the field of the numerical and experimental investigation on the dynamics of an underwater non-cohesive sediment deposit subjected to an impulsive forcing. The aim of this work is to provide the basis for the development of an innovative technique that could be applied to increase the effectiveness of sediment removal at the bottom of an artificial reservoir through the combined use of submerged explosions and flushing maneuvers. The first part of the paper deals with the early Smoothed Particle Hydrodynamics (SPH) 2D simulations of a gas explosion and interaction with heterogeneous media. Subsequently are illustrated the experimental tests concerning the injection of a cold CO2 jet from the bottom of a 2D laboratory tank containing water and a sand bed at initial rest condition: these experiments were carried out to provide a first insight in the physics of the water-sediment impulsive dynamics including some similarities with the underwater explosion inside a non-cohesive sediment layer at rest. Finally the experimental tests were simulated with the SPH method by introducing some severe approximations in order to handle heterogeneous materials. Both initial rest condition and flushing maneuver were investigated. Even if some improvements of the model are required, the results show good qualitative agreement with the experimental frames; the SPH model can therefore lead to a first evaluation of the scouring effect when the gas injection and flushing maneuvers are combined.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.