EFFECT OF MORPHOLOGICAL FORM IN SEDIMENT ACCUMULATION IN 2D OBSTACLE

Carlos Mendez¹; Christian Schaerer²

¹ Facultad de Ciencias Quimicas UNA; ² Polytechnic School, National University of Asuncion, Campus de la UNA

doi:10.20906/CPS/CILAMCE2015-0172

Resumo

The study of sediment transport processes is of interest to science and engineering because of their negative effects on the environment, mainly in watersheds and water reservoirs. Nearly 1\% of the total storage capacity reservoirs in the world is lost every year due to sediment accumulations. In addition the environmental degradation is strongly related to the transport of sediments. Normally the physical process of transport of sediments is studied either in laboratory flumes or using a specific hydraulic assembly. However, such experiments are time-intensive, costly and not always easy to conduct. In this context, the numerical simulation can reduce costs and improve the understanding of the relevant flow and transport phenomena. There are strong, and unknown relations between the morphology of an obstacle and the sediment accumulation around it. This relation is influenced by the flow and the characteristic of the sediment. We begin our analysis observing the possible accumulation regions formed by the presence of swirls. In this context, the main objective of this work consists in determining the presence of accumulation zones for different obstacles shapes. In this work, the effects of the morphological shape in the accumulation of sediments in a 2D water/obstacle system is investigated for several obstacles shapes. To this end, a two- dimensional numerical simulation with simultaneous fluid flow and scalar transport model are used. The different forms of the obstacles are subjected to the same flow conditions in order to detect the scalar accumulation. To solve the non-stationary incompressible Navier-Stokes equation we use the CBC.PDESys package from dolphin base code. The sediment transport is represented by a scalar transport equation, which is justified by the interest to determine accumulation zones for a great quantity of shapes. The validation schemes include comparison between laboratory results in flumes with numerical simulation.

Palavras-chave: Scalar transport; Sediment accumulation; Shape influence