Dienstag 25.10.2005 16:00 Uhr  Dr. Adam Szymkiewicz, Institute of Hydroengineering of the Polish Academy of Sciences 
Generalized macroscopic model for unsaturated water flow in binary porous
media Binary porous media are composed of two materials having different
hydraulic properties. According to the asymptotic homogenization theory,
the unsaturated flow in such type of media is described with various
models, depending on the ratio of the hydraulic diffusivity of the two
components and the connectivity of the most conductive component. It can
be shown that a continuous passage between various models exist. It is
also possible to deduce a generalized model, suitable for the entire range
of the diffusivity ratio. The obtained results are compared with other
models that can be found in the literature. 
Dienstag 08.11.2005 16:00 Uhr  Dr.Ing. Arne Färber, Universität Stuttgart, Institut für Wasserbau, Lehrstuhl für Hydrologie und Geohydrologie 
Thermal InsituRemediation Principles for Contaminated Soils: Do Processes or Structures Prevail Thermal InSitu remediation techniques are increasingly used to clean up
soils from contaminants. Compared to most other "enhanced" methods, they
dispose of a significant advantage, improving their efficiency
substantially: heat conduction helps to "crack down" the
"diffusionlimitproblem", which acts in many practical cases as the
unsurmountable barrier for ordinary insitu methods. Thus these methods
may help to save a lot of time (and money). Nevertheless the limits for
thermal technologies are evident as well. The presentation will show
this by some experimental examples. Although the role of heterogeneous
structures is apparent and for thermal methods can sometimes be
considered by very simple approaches in order to predict the cleanup
process, yet a thorough and consistent analysis is difficult to obtain
due to the complex interaction between the various dominating processes
and the structures involved. Thus the question in the title can be
answered according to Radio Eriwan. 
Dienstag 15.11.2005 16:00 Uhr  Maarten Felix, Universität Stuttgart, Institut für Wasserbau, Lehrstuhl für Hydromechanik und Hydrosystemmodellierung 
Dilution of sediment gravity currents, or: the generation
of turbidity currents from debris flows Abstract:
Sediment gravity currents are a subclass of density
currents, which are currents driven by the density
difference with the ambient fluid. In sediment gravity
currents this density difference is caused by sediment.
Such flows occur in many different environments, both
subaerially and subaqueously, but the flows considered
in this talk will be subaqeous only. Sediment concentration
in sediment gravity flows can range from dense (debris
flows with 6070 % volumetric concentration of sediment)
to dilute (turbidity currents with less that 1 %
sediment).
Several mechanisms have been suggested to explain how dense
flows can transform into dilute flows, but none appear
to be entirely satisfactory. In this talk, results will
be presented from laboratory experiments, numerical
simulations and from field work, aimed at gaining a
better understanding of dilution/transformation processes. 
Dienstag 22.11.2005 16:00 Uhr  Dr. Sebastian Geiger, ETH Zürich, Institute of
Isotope Geochemistry and Mineral Resources 
Hydrodynamic and thermodynamic modelling of NaClH2O fluids: Groundwater flow
below volcanoes Abstract:
Many important geological processes in the shallow Earth's crust are
related to the simultaneous, often buoyancy driven, movement of heat and
dissolved salt (NaCl) in waterrich fluids. These processes encompass
the formation of large metallic ore deposits below volcanoes, the
cooling of newformed oceanic crust along midocean ridges, convection
in sedimentary basins, or heat transported by fluid flow in geothermal
systems.
The hydrodynamic and thermodynamic behavior of NaClH2O fluids in
permeable rocks is fundamentally different from that of pure H2O. During
thermohaline convection, socalled doublediffusive and
doubleconvective flow patterns can evolve, because heat diffuses at a
higher rate than salt while salt is advected at a faster rate than heat.
NaClH2O fluids can also separate into two fluid phases, a highdensity,
highsalinity brine and lowdensity, lowsalinity vapor, at pressures
and temperatures well above the critical point of pure H2O (374oC, 221
bar), which is likely a key driver for the formation of the world's
major ore deposits of Cu, Mo, Au and other important metals.
Previous numerical studies of thermohaline convection have either
assumed that the fluid is incompressible and the Boussinesq
approximation applies or, in the case of phase separation, that the
fluid is pure water. This, however, does not account for the full
complexity of thermohaline convection including phase separation at
hightemperature and highpressure. This talk will discuss new numerical
approaches for modelling the hydrodynamics and thermodynamics of
NaClH2O fluid flow and present results related to the formation of
economic ore deposits. 
Freitag 25.11.2005 11:00 Uhr  Philip Binning, Associate Professor in Subsurface Hydrology and Numerical Modelling, Institute of Environment & Resources, Technical University of Denmark 
A catchment scale model for assessing the risk associated with point
source contaminated sites Point sources are one of the main threats to groundwater quality. It is
essential that remediation efforts are prioritised to ensure that the
point sources which constitute the largest groundwater risk are
remediated first. Currently, no systematic procedure is available for
evaluating and comparing the contamination risk associated with various
point sources within a catchment area. Here a simple method is presented
that provides the basis for a ranking of point sources according to
their impact on groundwater quality. The method is designed for real
catchments where data availability is a major limitation on risk
assessment. The model consists of two components: a source model and a
large scale transport model. The source model describes the discharge of
contaminant from a polluted site where the source of contaminant is
located both in the unsaturated zone and in a secondary aquifer. It
includes separate phase organics and degradation processes. The
transport model applies particle tracking for simulating groundwater
flow and residence time in the aquifer. The solute transport description
includes sorption effects as well as transformation processes.
Degradation is spatially variable and depends on the redox conditions in
the aquifer.
The risk assessment concept was tested at a contaminated site,
Østerparken 57, located in Tåstrup, Denmark. The site is heavily
contaminated with TCE, where residual phase in a hot spot in the
unsaturated zone and the secondary aquifer is present. The simulations
performed with the developed models show that the contamination at
Østerparken 57 poses a large risk for the groundwater resource both
locally and at the catchment scale. This risk will be present for an
extended period of time. Sensitivity and scenario analyses were
performed to identify the most critical parameters for the risk
assessment of Østerparken. Comparisons with existing risk assessment
tools were also made.

Freitag 25.11.2005 11:00 Uhr  Birgitte Eikemo und Helge Dahle, University of Bergen, Norway 
A discontinuous Galerkin Method for Computing Flow in Porous Media We consider a discontinuous Galerkin scheme for flow in heterogeneous
media. An efficient solution of the resulting system of unknowns is
possible by taking advantage of a priori knowledge of the direction of
flow. By arranging the elements in a suitable sequence, the full
system need not be assembled and one may compute the solution in an
element by element fashion. We demonstrate this procedure on
boundaryvalue problems for time of flight and tracer flow. 
Mittwoch 07.12.2005 11:00 Uhr  Dr. Hans Bruining, TU Delft, Faculty of Civil Engineering and Geosciences / Dept. of Geotechnology 
Upscaled model, derived from homogenization, for water drive recovery in fractured reservoirs Zusammenfassung:
Homogenization is a powerful method to obtain upscaled equations in
situations where a clear separation of scales is possible. The ratio of
the small scale with respect to the large scale is denoted by e. The
method has been used successfully for a variety of porous media flow
problems, e.g. for reactive convection diffusion flows, two phase flow
in heterogeneous media, nonNewtonian flow and flow in fractured
reservoirs. In this contribution our interest is in water drive recovery
from waterwet fractured reservoirs. Our approach follows the ideas of
T. Arbogast (TIPM). However, the emphasis in this contribution is on (1)
the physical assumptions used in the derivation of the upscaled equation
to leading order of e, (2) the use of dynamic constitutive relations
(capillary pressures and relative permeabilities) proposed by Barenblatt
et al. to obtain the matrix imbibition contribution and (3) the correct
implementation of the imbibition contribution in the combined
fracturematrix model.
The numerically computed results are compared to the results obtained
with the semiempirical dualporositytransfer function method
conventionally used by petroleum engineers in their simulators. The
advantages of using homogenization for the derivation of transfer
functions are discussed. 
Montag 09.01.2006 16:00 Uhr  Prof. Christoph Clauser, Institut für
Angewandte Geophysik, RWTH Aachen 
Simulation von reaktivem Transport und Permafrost in porösen und geklüfteten
Reservoiren 
Dienstag 10.01.2006 16:00 Uhr  Dr. Ivan Lunati, Inst.f. Hydromechanik u. Wasserwirtschaft, ETH Zürich 
A Multiscale FiniteVolume Framework for Modeling Multiphase Flow A multiscale finitevolume (MSFV) method for solving multiphase flow
problem in highly heterogeneous media was recently developed. In
contrast with classical upscaling techniques, the goal of multiscale
methods is not simply to capture the largescale effects of the
finescale heterogeneity, but to provide an efficient tool for solving
large flow problems with finescale resolution.
The MSFV is based on a fractional flow formulation of the problem:
first an equation for the total velocity is solved, then a finescale
velocity field is reconstructed, finally the phasesaturation
distribution is obtained by solving the nonlinear transport equations.
In addition to the original fine grid the MSFV method employs an
imposed coarse grid and a dual coarse grid. The first step is to
compute the effective parameters that have to be used for solving the
global flow problem on a coarse grid. This is done by means of a set of
basis functions, which are numerical solutions computed on the cells of
the dual grid. From these basis functions, the fluxes across the
coarseblock boundaries are computed and the transmissibilities are
extracted. Then the conservative finescale totalvelocity field is
reconstructed by solving a local flow problem in each coarse cell. 
Dienstag 24.01.2006 16:00 Uhr  Prof. Peter King, Department of Science and Engineering, Imperial College London, U.K 
Entropymediated structurepermeability relations in skeletal porous materials The aim of this paper is to formulate a new framework for characterisation of porous
materials and for obtaining firstprinciples structurepermeability relaions. The
formaslism is based on a representation of the porous medium in skeletal form and involves
several steps. First, the skeleton is characterised by a new fabric tensor that describes
the local pore structure. Second, the fabric tensor is used to construct a configurational
entropy of the porous medium, based on Edwards??? compactivity concept. Both the fabric
tensor and the entropic analysis are initially illustrated in twodimensions and are then
extended to threedimensional systems. Third, the local porescale permeability is expressed
in terms of the structure of the skeleton and the degrees of freedom that comprise the phase
space of configurational states. Fourth, the porescale permeability is calculated as an
expectation value over the partition function.
We propose that the same procedure can be used to find the conductivity of the porous medium
when it is filled with brine water. This makes it possible to derive a theoretical relation
between these two transport properties. 
Dienstag 14.02.2006 16:00 Uhr  Dipl.Math. Stefan Rief, Fraunhofer ITWM, Strömung und komplexe Strukturen, 67657 Kaiserslautern 
Nonlinear Flow in Porous Media  Numerical Solution of the NavierStokes System with Two Pressures and Application to Paper Making 
Donnerstag 30.03.2006 10:00 Uhr  Majid Hassanizadeh, Professor of Environmental Hydrogeology, Department of Earth Sciences, Utrecht University 
150 Years of Darcy's Law  A critical look at the theories of twophase flow in porous media
Darcy's law was proposed in 1856 to describe the flow of constantdensity
water in homogeneous, isotropic, nondeformable sand under isothermal
conditions. Since then, that simple formula has been "extended" to be valid
for flow of more fluids, with variable density, in heterogeneous,
anisotropic, deformable sand under nonisothermal conditions. The extension
has been achieved by adding bells and whistles to the simple equations that
was proposed by Darcy.
In this presentation, we briefly describe this metamorphosis of Darcy's law
and show that no real physics is actually introduced into the extended
versions. In particular, we study the models of capillary effects in
traditional multiphase (and unsaturated) flow theories. Commonly, we assume
that there is an algebraic relationship between capillary pressure and
saturation. This relationship is based on measurements made under static
conditions. This static relationship is then used to model dynamic
conditions. However, it is a known fact that there is no unique relationship
between capillary pressure and saturation. There are both hysteretic and
nonequilibrium effects. We discuss new capillarity theories which are
potentially devoid of hysteresis and include an additional term accounting
for dynamic (or nonequilibrium) capillarity effects. There is compelling
experimental evidence reported in the literature that the nonequilibrium
effect is observable, quantifiable, and significant. In this presentation,
we provide theoretical and experimental evidences of the validity of new
theories. We then focus on the dynamic effect and use porescale and
continuum scale simulation results to show the possible significance of the
dynamic effect at various scales. We also investigate how the extended
capillary equation affects mathematical models of unsaturated and twophase
flow models.
