The Library
Modeling solute transport and mixing in porous media under turbulent flow conditions : application to the hyporheic zone
Tools
Baioni, Elisa (2021) Modeling solute transport and mixing in porous media under turbulent flow conditions : application to the hyporheic zone. PhD thesis, University of Warwick.
|
PDF
WRAP_Theses_Baioni_2021.pdf - Submitted Version - Requires a PDF viewer. Download (49Mb) | Preview |
Official URL: http://webcat.warwick.ac.uk/record=b3853248
Abstract
The thesis proposes a modeling approach to quantify the solute transport and mixing in porous media under turbulent flow conditions. The study is motivated by the significant implications of solute transport processes in the hyporheic zone to the natural attenuation of pollutants and the lack of a complete model for predicting the complex phenomena characterizing such environment. The first part of the thesis tackles the quantification of the vertical variation of the effective diffusion coefficient under a turbulent flow in a porous medium across the sediment-water interface representative of solute transport and mixing in the hyporheic zone. Recent experimental results show an exponential reduction of the diffusion coefficient with depth below the exchange interface. This work expands these recent results by estimating the uncertainty associated with the spatially variable diffusion coef- ficients for different combinations of (a) the sediment grain size and (b) the turbulence level at the water-sediment interface. A Bayesian inverse method implemented through an acceptance/rejection algorithm is employed to obtain the depth-resolved posterior probability distributions of the effective diffusion coefficient. The second part concerns the development and testing of the modeling approach implemented by combining (a) the Skew Brownian Motion (SBM) model, predicting the solute particles' behavior across media with spatially variable diffusivity, and (b) the Parameterized scalar profile (PSP) mixing model, quantifying the temporal evolution of chemical concentration due to turbulent mixing. The approach addresses the spatial variability of the diffusion coefficient and yields predictions of the concentration probability density function. The model is applied to a system constituted by a porous medium underlying a clear water column where turbulent ow is generated. A rigorous sensitivity analysis is performed to evaluate the influence of model parameters on solute concentrations and mixing. The study highlights that the vertical exponential decay of the diffusion coefficient observed only in a limited range of dimensionless depths has a marked influence on solute mixing and transport. The model can be extended to reactive transport.
Item Type: | Thesis (PhD) | ||||
---|---|---|---|---|---|
Alternative Title: | Modelling solute transport and mixing in porous media under turbulent flow conditions : application to the hyporheic zone | ||||
Subjects: | Q Science > QC Physics T Technology > TA Engineering (General). Civil engineering (General) T Technology > TC Hydraulic engineering. Ocean engineering |
||||
Library of Congress Subject Headings (LCSH): | Turbulence, Hyporheic zones, Porous materials, Porous materials -- Fluid dynamics, Porous materials -- Transport properties, Sediment transport | ||||
Official Date: | December 2021 | ||||
Dates: |
|
||||
Institution: | University of Warwick | ||||
Theses Department: | School of Engineering | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Nezhad, Mohaddesh Mousavi | ||||
Sponsors: | University of Warwick. School of Engineering ; Politecnico di Milano. Dipartimento di Ingegneria Civile e Ambientale ; WISC | ||||
Format of File: | |||||
Extent: | xxxiii, 268 leaves : illustrations | ||||
Language: | eng |
Request changes or add full text files to a record
Repository staff actions (login required)
View Item |