Browsing by Author "Neuweiler, Insa"

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Open Access
Scale dependence of flow and transport parameters in porous media
(2006) Neuweiler, Insa; Helmig, Rainer (Prof. Dr.)
The study discusses the problem of the influence of spatial scales on modeling of flow and transport processes in porous media. As soil and rock formations are usually heterogeneous, this problem is strongly coupled to the question as to how information about structure is transported over length scales. On different length scales different driving forces determine flow and transport processes. In order to derive an appropriate model for a certain scale of interest it is crucial to include information about the impact of structure on smaller scales into the model. The transfer from a detailed heterogeneous model to an equivalent model on a larger scale, where averaged properties are described, is called upscaling. To derive an upscaled model the following questions have to be addressed: • What are the relevant time scales and length scales? • What are the relevant processes on the scale, where heterogeneities are resolved? • How does the upscaled model look like? • What are the effective parameters for the upscaled model? As detailed information about the parameter distribution in the heterogeneous model is in most cases not known or it is not possible to deal with the exact distribution, further questions have to be addressed: • How can the effective parameters be approximated based on incomplete knowledge about the parameter distribution? • What are the relevant quantities to characterize the heterogeneous distribution and how can they be taken into account? Upscaling for different two-phase flow problems in porous media is discussed in the study.