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Generalized CTRW for Transport in Heterogeneous Porous Media
The generalized CTRW method can be used to simulate streamlines in heterogeneous porous media. Validation studies showed that the transversal spreading deviates from the expected behavior. An addition to the model is currently under development to overcome these flaws.
Keywords: stochastic processes, porous media, CTRW, transport, heterogeneous, 2D, streamline, random walk
Flow and transport in porous media is a relevant topic in many engineering applications and the environmental sciences. Stochastic processes have proven to be useful under the typically very uncertain conditions of such problems.
One of these methods, the generalized Continuous Time Random Walk (CTRW) model, is currently used at IFD to analyze two-dimensional streamlines in random heterogeneous porous media. In this context the streamlines are approximated by polygonal chains with constant segment lengths (L). Each segment is thus characterized by an angle (A) and an average absolute velocity (U). The generalized CTRW method describes transitions between subsequent segments by a Markov process. In this work, the implementation is based on transition matrices as discrete conditional probability density functions (PDFs).
Tracer plumes for different types of random fields have been investigated to validate the method. While reference results in the mean flow direction are well recovered, the transversal results are not as good as expected.
Current efforts target the weak performance in the transversal direction. An additional model is sought to complement the existing method by incorporating further variables.
Flow and transport in porous media is a relevant topic in many engineering applications and the environmental sciences. Stochastic processes have proven to be useful under the typically very uncertain conditions of such problems. One of these methods, the generalized Continuous Time Random Walk (CTRW) model, is currently used at IFD to analyze two-dimensional streamlines in random heterogeneous porous media. In this context the streamlines are approximated by polygonal chains with constant segment lengths (L). Each segment is thus characterized by an angle (A) and an average absolute velocity (U). The generalized CTRW method describes transitions between subsequent segments by a Markov process. In this work, the implementation is based on transition matrices as discrete conditional probability density functions (PDFs). Tracer plumes for different types of random fields have been investigated to validate the method. While reference results in the mean flow direction are well recovered, the transversal results are not as good as expected. Current efforts target the weak performance in the transversal direction. An additional model is sought to complement the existing method by incorporating further variables.
The goals will be defined before the project start.
The goals will be defined before the project start.
Interested candidates please send an email with a recent transcript of records to: oliver.brenner(at)ifd.mavt.ethz(dot)ch
Interested candidates please send an email with a recent transcript of records to: oliver.brenner(at)ifd.mavt.ethz(dot)ch