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Seminar by Dr. Fabian A. Bombardelli

Date: Mon., April 25, 2016
Place: PACCAR 202
Time: 10:10 a.m.—11:00 a.m.

EXPLAINING THE INTRICACIES OF SEDIMENT TRANSPORT AT DIFFERENT SCALES WITH COMPUTATIONAL AND THEORETICAL APPROACHES
Examples of multi-phase flows are diverse: dust storms, sediment transport in rivers and estuaries, bubble plumes, and many other natural and man-made applications. To study sediment transport, the field is transitioning from old regressions of last 70 years, to mechanistic models, which combine deterministic and stochastic approaches. For reasons which are unclear, and despite the leadership of civil engineers in the field of sediment transport, the theory of two-phase flows has been developed elsewhere. These models address the interaction of carrier and disperse phases.
Still, it is not clear what to use for a given level of concentration, and for the objective of a given study. Furthermore, the action of turbulence needs to be quantified carefully depending on the problem at hand, and phenomena such as sediment entrainment need to be accounted for.
In this presentation, I describe a novel framework to analyze sediment transport, which clearly puts forward a pathway for the analysis of a host of problems. We present the application of this framework to solve the problem of sediment in suspension. For the case of transport of sediment as bed-load, we present a Lagrangian model which tracks each particle individually and addresses the Non-Fickian behavior of the particles; followed by a new computational algorithm for the Basset force. Finally, we describe theoretical and numerical approaches to deal with two-phase flows. The presentation concludes with an analysis of future work and the challenges to overcome

Examples of multi-phase flows are diverse: dust storms, sediment transport in rivers and estuaries, bubble plumes, and many other natural and man-made applications. To study sediment transport, the field is transitioning from old regressions of last 70 years, to mechanistic models, which combine deterministic and stochastic approaches. For reasons which are unclear, and despite the leadership of civil engineers in the field of sediment transport, the theory of two-phase flows has been developed elsewhere. These models address the interaction of carrier and disperse phases.
Still, it is not clear what to use for a given level of concentration, and for the objective of a given study. Furthermore, the action of turbulence needs to be quantified carefully depending on the problem at hand, and phenomena such as sediment entrainment need to be accounted for.
In this presentation, I describe a novel framework to analyze sediment transport, which clearly puts forward a pathway for the analysis of a host of problems. We present the application of this framework to solve the problem of sediment in suspension. For the case of transport of sediment as bed-load, we present a Lagrangian model which tracks each particle individually and addresses the Non-Fickian behavior of the particles; followed by a new computational algorithm for the Basset force. Finally, we describe theoretical and numerical approaches to deal with two-phase

A seminar by Dr. Eric Edwards
Friday, April 22 at 3:10pm in UI Hubert room 27

ABSTRACT
We present a lobby model to explain the adoption and persistence of seemingly costly environmental  policies relative to the likely benefits generated. The arguments of the model are illustrated by water  trade restrictions for mining firms in the Atacama Desert of northern Chile. The area is one of the driest  in the world but also the world’s top copper producer. Due to regulation of access to local water in  the region, firms have begun using desalinated water at a cost of up to $19,542 per m3/day while agricultural  water trades at median price of $343 per m3/day. We explore how governmental maintenance of environmental  and indigenous water supplies through restrictions on water trades causes these large price differentials.  We provide a simple framework that explains how this type of policy can be supported under reasonable  assumptions about lobbying. Interest group lobbying, limited information to unorganized general citizens  about policy costs and benefits, and their associated distribution can lead to strong regulation, even  when the protected environmental areas and agricultural populations are small and isolated. Differencein-  difference modeling of sector prices indicates that after an abrupt increase in regulatory denials,  prices diverged in a manner consistent with the lobbying model. Using market price and desalination  cost data, policy costs are estimated at $6.15 billion dollars or approximately $350 per citizen, which  may or may not equate to perceived general benefits.

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