Session overview and description:

Physics of flow and transport:

The interaction of various forces (capillarity, gravity, mechanical pressure and buoyancy) in a heterogeneous structure results in a complex motion of fluids and solutes. To predict flow and transport, the governing equations must often be simplified. The goal of this session is to analyze the accuracy of flow and transport equations at the pore and at the Darcy scale. In addition, the physics behind the measurement techniques to analyze heterogeneous media will be discussed.

Keynote:

• Dani Or, Soil Science, Architecture, Civil and Environmental Engineering, EPFL Lausanne
• Allen Hunt, Department of Physics and Department of Geology, Wright State University
  

Reconstruction of pore scale geometries:

Flow and transport in porous media are dominated by the distribution of the fluid phases, a property depending on the geometry of the pore space. To predict distribution and flow of the fluids, the complex pore structure must be quantified. By means of tomography and image analysis, various properties of the pore scale can be computed. From the manifold of these properties, the most characteristic for the fluid distribution must be determined. To analyze the effect of the geometrical properties, models of porous media with well defined mathematical characteristics are generated by means of stochastic geometry.

Keynote:

• Hans-Jörg Vogel, Soil Physics, Centre for Environmental Research, Leipzig
• Hans Rudolf Künsch, Seminar für Statistik, Swiss Federal Institute of Technology, ETH Zurich

Numerical methods for simulation of flow and transport on the pore scale:

Material parameters like the capillary pressure and relative permeabilities for porous media can be obtained by direct numerical simulation of multiphase system on the pore scale. In this session numerical methods using the explicit geometry of a porous medium are presented and analyzed with respect to their capabilities to predict material parameters, fluid phase distribution, dispersivities and dynamic effects.

Keynote:

• Stéphane Zaleski, Laboratoire de Modélisation en Mécanique, Université Pierre et Marie Curie, Paris
• Jonathan Summers, EFM Research, School of Mechanical Engineering, University of Leeds

Upscaling approaches 1:

From pore scale to Darcy scale It is an open discussion, how pore space characteristics can be reflected by Darcy scale model parameters, such as e.g. relative permeability for two-phase flow. Also, models for the Darcy scale have often been derived making assumptions about the pore scale processes, which are not necessarily met in reality. Transient two-phase flow on the pore scale can lead e.g. to a dynamic term in the Darcy scale model, an effect which is discussed intensely. The topic of this session is the prediction of model parameters and processes for flow and transport processes on the Darcy scale, based on information about the structure of the pore space and the processes on this scale. These questions involve different methods, such as the application of pore network models, percolation theory or other theoretical approaches.

Keynote:

• Mike Celia, Department of Civil and Environmental Engineering, Princeton University

Upscaling approaches 2:

Darcy scale including heterogeneities The topics of this session are upscaling approaches for flow and transport problems from Darcy scale to field scale. An important question is the characterization and quantification of heterogeneity on these scales as well as appropriate upscaling methods to incorporate them. Different approaches could be applied to achieve this, such as stochastic approaches or effective medium theory. The averaged transport or flow behaviour may have to be captured by properties or processes in the upscaled models, which are not present on the small scale (such as e.g. large scale hysteresis effects or anisotropy of the parameters). Using inverse modelling to investigate the occurrence of such effects and their relation to the structure of the soil heterogeneity is another important issue.

Keynote:

• Majid Hassanizadeh, Department of Earth Sciences, Faculty of Geosciences, Utrecht University

Numerical modelling concepts including extended constitutive relationships:

The description of multi-phase flow on the macro-scale has so far mostly been modelled assuming equilibrium conditions and accounting for a single observation scale. The former might not be valid in the case of rapidly changing flow conditions while the latter cannot incorporate effects of small-scale heterogeneities or locally occurring processes of greater complexity. This session will focus on two questions: How can the effects of non-equilibrium conditions be incorporated in the constitutive relationships with for example a dynamic term or a hysteresis model? And second, are multi-scale techniques adequate for including small-scale processes?

Keynote:

•  Irina Ginzburg, Ouvrages pour le Drainage et l’Etanchéité, Centre d’Antony, CEMAGREF
• Rudolf Hilfer, Institut für Computerphysik, Universität Stuttgart

Lab- scale testing of structures and flow:

Breakthrough curves or hydraulic conductivities of a soil column depend on the arrangement of the porous media. So, from the measured effective properties, the existence of heterogeneities can be reconstructed. In addition, by means of new imaging techniques, the spatial and temporal distribution of the flow field can be measured directly.

Keynote:

• Dorthe Wildenschild, Civil, Construction and Environmental Engineering, Oregon State University

Field- scale testing of structures and flow:

In natural field soils, the assumption of a homogeneous system that can be simplified by one dimensional description is almost never justified. Instead, layers, fissures and local variations in the composition of the constituting materials cause a heterogeneous flow field. The goal of this session is to classify the measured effects of transport relevant heterogeneities and to link these characteristics to structures and processes.

Keynote:

• Jan Vanderborght, Institute of Chemistry and Dynamics of the Geosphere, Forschungszentrum Jülich.