Wolfgang Kinzelbach

Numerical Modeling of Natural and Enhanced Denitrification Processes in Aquifers

Nitrate modeling in the groundwater environment must incorporate microbial denitrification as the major process of nitrate elimination. A multispecies transport model is presented which describes the interaction of oxygen, nitrate, organic carbon, and bacteria. Three phases (mobile pore water, biophase, and aquifer material) are taken into account. The model is applied to a natural aquifer situation as well as to an in situ remediation case where nitrate is employed as an oxidant. In the natural aquifer it is shown that the release of organic carbon from the matrix is the controlling factor for denitrification. In the remediation case, on the other hand, the data suggest that diffusion limitation of the nutrient supply to the biophase controls bacterial growth.

Lagrangian measurement of vorticity dynamics in turbulent flow

The full set of velocity derivatives,

Temporal behavior of a solute cloud in a heterogeneous porous medium: 1. Point‐like injection

\partial u_{i}/\partial x_{j}

Simulation of reactive processes related to biodegradation in aquifers. 1. Structure of the three-dimensional reactive transport model

, is measured experimentally in a Lagrangian way in quasi-homogeneous isotropic turbulence. This is achieved by applying the three-dimensional particle tracking velocimetry (3D-PTV) technique to an electromagnetically forced flow with

Continuous groundwater velocity fields and path lines in linear, bilinear, and trilinear finite elements

\hbox{\it Re}_{\lambda}\,{\thickapprox}\,50

Influence of Microbial Growth on Hydraulic Properties of Pore Networks

. Checks based on precise kinematic relations show that the technique presented measures the velocity derivatives with good accuracy. In a study on vorticity, characteristic properties of turbulent flows known from direct numerical simulations are reproduced. These are the positive skewness of the intermediate eigenvalue of the rate of strain tensor,

Interaction between water flow and spatial distribution of microbial growth in a two-dimensional flow field in saturated porous media.

s_{ij}

The saltpool benchmark problem – numerical simulation of saltwater upconing in a porous medium

,

Environmental tracer transport (3H and SF6) in the saturated and unsaturated zones and its use in nitrate pollution management

\langle \Lambda_{2}\rangle \,{>}\,0

Temporal behaviour of a solute cloud in a chemically heterogeneous porous medium

, the predominance of vortex stretching over vortex compression,