Séminaire de Rainer H. Helmig (University of Stuttgart, Germany) / Darcy Lectures #1


Le mercredi 25 février 2015 à 16h30, en salle de conf de l'OSUR (campus de Beaulieu, bât.

Le mercredi 25 février 2015 à 16h30, en salle de conf de l'OSUR (campus de Beaulieu, bât. 14B, RDC), Rainer H. Helmig propose un séminaire intitulé

Modeling and Analysis of Soil-Moisture Processes in the Subsurface: The Influence of Evaporation and Salt Precipitation in Groundwater

Cette présentation est proposée dans le cadre des Darcy Lecture Series in Groundwater Science

Rainer H. Helmig, Ph.D., is head of the Department of Hydromechanics and Modelling of Hydrosystems at the Institute for Modelling Hydraulic and Environmental Systems, University of Stuttgart, Germany. His research covers fundamental research and applied science in the field of porous-media flow. A major focus is on developing methods for coupling hydrosystem compartments and complex flow and transport processes. This is based on simulation methods and techniques for describing single- and multiphase, multicomponent flow and transport processes in the subsurface, i.e., in porous and fractured-porous media.

During this presentation, you will discover how soil-moisture processes in the subsurface play a crucial role in the hydrological cycle and the groundwater budget.

This zone is subject to both natural and human-induced disturbances, resulting in continually changing soil structure and hydraulic and mechanical properties. The mass-and heat-flux processes across the land/atmosphere interface controlled by the dynamic interaction between the atmospheric boundary layer and the land surface in conjunction with the natural and induced heterogeneities control the spatial and temporal distribution of soil moisture in this shallow and complex zone of the subsurface.
Understanding soil-moisture conditions in this zone is of interest in various applications in hydrology, such as land-atmospheric interaction, soil evaporation and evapotranspiration, and climate modeling, as well as emerging problems in assessing the risk of, for example, the leakage of carbon dioxide or methane from deep geological formations to the shallow subsurface that affects groundwater quality and vegetation. In this lecture, you will learn about:

  • # Relevant processes of mass, momentum, and energy transfer at the interface between a free-flow and a porous-media system

  • # Conceptual modeling for coupled single-phase free flow and two-phase porous-medium flow with a detailed description of the models in the free flow and in the porous medium

  • # A new coupling concept for modeling coupled porous-medium and free flow with application to evaporation and salt-precipitation processes; a comparison study will show the advantages and disadvantages in comparison with classical approaches

  • # Three model combinations for evaporation processes and how to use them to study the effects of various quantities and processes — a porous-medium model coupled with a laminar free-flow model, a simple boundary-layer model, and a Reynolds-averaged turbulence model that uses algebraic expressions to account for the turbulent flow behavior; these model combinations are employed to evaluate the influence of different parameters and processes on the computed drying rates — the results will be compared and discussed with experimental measurements on different scales

  • # Various numerical examples that will illustrate the influence of soil-moisture processes in the subsurface on the groundwater budget and quality.

Contact :
Rainer H. Helmig (University of Stuttgart, Germany)

Contact OSUR :
Paulina Pia Lopez (Géosciences Rennes)

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