scholarly journals Modeling and experimental study of the effect of pore water velocity on the spectral induced polarization signature in porous media

2021 ◽  
Author(s):  
Kuzma Tsukanov ◽  
Itamar Assa ◽  
Nimrod Schwartz
Keyword(s):  
Experimental Study ◽  
Porous Media ◽  
Pore Water ◽  
Induced Polarization ◽  
Water Velocity ◽  
Pore Water Velocity ◽  
Spectral Induced Polarization

Experimental and numerical investigation of microparticle transport and deposition in the context of permafrost thaw

2021 ◽  
Author(s):  
Madiha Khadhraoui ◽  
John Molson ◽  
Najat Bhiry
Keyword(s):  
Porous Media ◽  
Pore Water ◽  
Water Velocity ◽  
Kinetic Term ◽  
Column Experiments ◽  
Order Kinetic ◽  
Permafrost Degradation ◽  
Pore Water Velocity ◽  
Laboratory Column ◽  
Study Laboratory

<p>In natural porous environments, soil particle migration during flow plays an important role in soil stability and pollutant transport by affecting soil mechanical properties and water quality. In northern areas, permafrost degradation alters the subsurface connection pathways leading to mass movements and rearrangement of the soil. To date, few models have included the influence of temporal and spatial variations of flow velocity and porous media heterogeneity on the transport and deposition of suspended particles.</p><p>In this study, laboratory column experiments and a numerical model were used to investigate these issues. The laboratory column experiments were carried out under different flow rates and the effect of porous media heterogeneity was investigated using different grain size distributions. The soil columns were reconstituted from several samples taken in the studied site, the Tasiapik Valley, located in the discontinuous permafrost zone near Umiujaq, Nunavik, Québec. During the experiments, the spatio-temporal distribution of the porosity and the hydraulic conductivity was monitored using X-ray computed tomography imaging (CT-SCAN). Using the pore water velocity computed from the groundwater flow solution, the advection–dispersion transport equation with a first-order kinetic term for particle deposition was solved using the finite element model Heatflow/Smoker. The dependency of the attachment kinetics on the pore water velocity and on the porous media heterogeneity was included. The model was tested and validated with an analytical solution and calibrated with the experimental data. Our simulations highlight the roles of hydrodynamic conditions and soil characteristics on particle transport and deposition mechanisms and the susceptibility of the porous medium to thermo-suffosion in permafrost environments.</p>

scholarly journals Experimental Study of Spectral Induced Polarization Response Based on Laboratory Measurement

2018 ◽  
Vol 16 (2) ◽  
pp. 25
Author(s):  
Dicky Ahmad Zaky ◽  
Suparwoto Suparwoto
Keyword(s):  
Experimental Study ◽  
Grain Size ◽  
Measurement System ◽  
Test Sample ◽  
Induced Polarization ◽  
Spectral Parameters ◽  
Digital Oscilloscope ◽  
Spectral Induced Polarization ◽  
Voltage Amplifier ◽  
Size Model

The spectral induced polarization (SIP) method can provide apparent complex resistivity based on measurements of multi frequency. SIP method also can provide more detail information about physical properties of rocks and minerals because SIP can give spectral parameters or Cole-Cole parameters such as, changeability (m), time constant (τ) and frequency dependence (c). An Experimental study in laboratory has been conducted to knowing the SIP response of some test sample. The measurement system is built with digital oscilloscope Pico ADC-100 as device for sampling the input and output voltage. Amplifier is used to doubled up the signal and input differential. The range frequency of measurement is 10−2 Hz - 103 Hz. Porouspot Cu − CuSO4 is used to minimize the polarization at potential electrode. A Matlab listings is used to calculate the response of impedance and phase. The result from calibration that used the parallel circuit RC indicate that the measurement system was good. SIP response of porous model indicate that the response form an asymptotic resistivity, and the peak of phase is in the range frequency where the dispersion happen. The result also indicate that resistivity of small grain size model is larger than the big grain size model. Result from sample of mineralized rocks did not indicate a perfect SIP response, it is influenced by the contact between mineral and water was minimum.

scholarly journals Hydrodynamic dispersion characteristics of lateral inflow into a river tested by a laboratory model

2009 ◽  
Vol 13 (2) ◽  
pp. 217-228 ◽  
Author(s):  
P. Y. Chou ◽  
G. Wyseure
Keyword(s):  
Pore Water ◽  
Transport Model ◽  
Column Experiment ◽  
Breakthrough Curves ◽  
Water Velocity ◽  
Laboratory Model ◽  
Hydrodynamic Dispersion ◽  
Transport Parameter ◽  
Transport Parameters ◽  
Pore Water Velocity

Abstract. Groundwater and river-water have a different composition and interact in and below the riverbed. The riverbed-aquifer flux interactions have received growing interest because of their role in the exchange and transformation of nutrients and pollutants between rivers and the aquifer. In this research our main purpose is to identify the physical processes and characteristics needed for a numerical transport model, which includes the unsaturated recharge zone, the aquifer and the riverbed. In order to investigate such lateral groundwater inflow process, a laboratory J-shaped column experiment was designed. This study determined the transport parameters of the J-shaped column by fitting an analytical solution of the convective-dispersion equation for every flux on individual segments to the observed breakthrough curves of the resident concentration, and by inverse modelling for every flux simultaneously over the entire flow domain. The obtained transport-parameter relation was tested by numerical simulation using HYDRUS 2-D/3-D. Four steady-state flux conditions (i.e. 0.5 cm hr−1, 1 cm hr−1, 1.5 cm hr−1 and 2 cm hr−1) were applied, transport parameters including pore water velocity and dispersivity were determined for both unsaturated and saturated sections along the column. Results showed that under saturated conditions the dispersivity was fairly constant and independent of the flux. In contrast, dispersivity under unsaturated conditions was flux dependent and increased at lower flux. For our porous medium the dispersion coefficient related best to the quotient of the pore water velocity divided by the water content. A simulation model of riverbed-aquifer flux interaction should take this into account.

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