Detection of free vertical convection and double-diffusion in groundwater monitoring wells with geophysical borehole measurements

Berthold, Susann; Börner, F.

doi:10.1007/s00254-007-0936-y

Cited by 31 publications

(38 citation statements)

References 31 publications

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“…When the thermal conductivity of the fluid is much greater than the surrounding medium, this equation yields a critical Rayleigh number of 68, identical to the solutal convection case. For conditions more typical of the saturated zone, the critical Rayleigh number is approximately 149 (Berthold and Borner, 2008). Using the latter number to estimate when natural convection would dominate transport by diffusion in, again, a 5-cm diameter well, we see that a thermal gradient of 0.0035 K/m would be sufficient, which is approximately an order of magnitude lower than typical geothermal gradients.…”

Section: Numerical Modeling Methodsmentioning

confidence: 77%

“…The thermal gradients that drive convection close to the critical Rayleigh number are also sufficiently small that the temperature variations that describe the convective movement are difficult to measure accurately. Recently, Berthold and Borner (2008) conducted transient 2D simulations of thermally convective Navier Stokes flow to compare with observations of laser sheet illuminated convection in a tube in the laboratory. Like the above simulations of mixed forced and free convection however, those simulations describe a 2D rectangular flow domain.…”

Section: Thermal Convection In a Wellmentioning

confidence: 99%

See 1 more Smart Citation

An Assessment of Aquifer/Well Flow Dynamics: Identification of Parameters Key to Passive Sampling and Application of Downhole Sensor Technologies

Sanford¹,

Martin-Hayden²,

Plummer³

2014

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Distribution Statement A REPORT DOCUMENTATION PAGEForm Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. (From -To) REPORT DATE (DD-MM-YYYY) 07-11-2014 REPORT TYPE Draft Final Report DATES COVERED SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S) Strategic Environmental Research and Development Program 4800 MARK CENTER DRIVE, SUITE 17D08ALEXANDRIA VA 22350-3600 SERDP SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution is unlimited SUPPLEMENTARY NOTES ABSTRACTContaminant redistributive effects in wells are nearly always present. Complete mixing appears to be very common; however, it is not universal. There is a continual balance between inflowing contaminant stratification (where present) and factors driving in-well mixing. Findings here imply common and very small drivers are responsible for slow but vigorous mixing relative to the residence time of water flowing through a typical well screen. Therefore, a tendency toward homogenization is anticipated to be common in field conditions. Most wells should experience strong redistribution effects, but some wells may maintain stratification or perhaps re-stratify differently from the surrounding formation. Ongoing technical transfer of these findings will promote better understanding in the environmental community that wells often represent a mixed flow-weighted average of the adjacent formation chemistry. This better understanding will yield cost savings in both short-term and long-term timeframes by accelerating the approval process for non-purge alternative sampling strategies, including passive sampling and in situ sensor technologies. SUBJECT TERMSGroundwater monitoring, passive sampling, purging,

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Section: Numerical Modeling Methodsmentioning

confidence: 77%

Section: Thermal Convection In a Wellmentioning

confidence: 99%

An Assessment of Aquifer/Well Flow Dynamics: Identification of Parameters Key to Passive Sampling and Application of Downhole Sensor Technologies

Sanford¹,

Martin-Hayden²,

Plummer³

2014

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“…Results from earlier numerical modeling compare well with these experimental results. In numerical modeling, a mean velocity of 15 9 10 -5 m/s was found for a temperature gradient of 0.1 K/m (Berthold and Börner 2008), and the experimental investigations yielded a mean velocity of 9 9 10 -5 m/s. Both studies prove the existence of thermal convection for temperature gradients down to at least 0.07 K/m (numerical modeling) and 0.1 K/m (experimental investigations), respectively.…”

Section: Figmentioning

confidence: 96%

Investigation of thermal convection in water columns using particle image velocimetry

Berthold

Resagk

2012

Exp Fluids

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Particle image velocity measurements were applied on thermally driven convection at low Rayleigh numbers. In a model experiment using a water column heated from bottom and cooled from above, the velocity field was studied at different vertical temperature gradients. In the testing facility with high aspect ratio (about 19) representing a 1-m-long column with 5 cm diameter, occurrence of free convection was verified for destabilizing temperature gradients of 0.1-2 K/m. The PIV results revealed that significant flow exists already at low vertical temperature gradients. The velocity of the stable large-scale circulations increased linearly with temperature gradient (\1 K/m) from 8 9 10 -5 to 1 9 10 -3 m/s. At higher temperature gradients (1-2 K/m), a transition from quasistationary into time-dependent flow was observed, where convection cells changed position, number, and form temporarily. The motivation of this research was to gain more insight into density-driven convection in boreholes and groundwater monitoring wells.

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“…To derive the growth rates of the temperature and salinity interfaces, we consider the similarity solution of the heat equation for a fixed boundary concentration (Bergman et al, 2011):…”

Section: Analytical Validation Of a Stable Inflowmentioning

confidence: 99%

“…For example, double-diffusive processes like thermohaline staircasing have been successfully modelled in lakes (Schmid et al, 2003), although these systems are generally modelled with analytical or empirical formulations (Kelley et al, 2003;Schmid et al, 2004;Arnon et al, 2014). Other known numerical modelling studies consider double-diffusive convection in monitoring wells (Berthold and Börner, 2008) and the collection of thermal energy in solar ponds (Cathcart and Wheaton, 1987;Giestas et al, 2009;Suárez et al, 2010Suárez et al, , 2014. However, modelling these complex physical processes in shallow waters still imposes a major scientific and computational challenge (Dias and Lopes, 2006).…”

Section: Introductionmentioning

confidence: 99%

An axisymmetric non-hydrostatic model for double-diffusive water systems

2018

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Abstract. The three-dimensional (3-D) modelling of water systems involving double-diffusive processes is challenging due to the large computation times required to solve the flow and transport of constituents. In 3-D systems that approach axisymmetry around a central location, computation times can be reduced by applying a 2-D axisymmetric model set-up. This article applies the Reynolds-averaged NavierStokes equations described in cylindrical coordinates and integrates them to guarantee mass and momentum conservation. The discretized equations are presented in a way that a Cartesian finite-volume model can be easily extended to the developed framework, which is demonstrated by the implementation into a non-hydrostatic free-surface flow model. This model employs temperature-and salinity-dependent densities, molecular diffusivities, and kinematic viscosity. One quantitative case study, based on an analytical solution derived for the radial expansion of a dense water layer, and two qualitative case studies demonstrate a good behaviour of the model for seepage inflows with contrasting salinities and temperatures. Four case studies with respect to doublediffusive processes in a stratified water body demonstrate that turbulent flows are not yet correctly modelled near the interfaces and that an advanced turbulence model is required.

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Detection of free vertical convection and double-diffusion in groundwater monitoring wells with geophysical borehole measurements

Cited by 31 publications

References 31 publications

An Assessment of Aquifer/Well Flow Dynamics: Identification of Parameters Key to Passive Sampling and Application of Downhole Sensor Technologies

An Assessment of Aquifer/Well Flow Dynamics: Identification of Parameters Key to Passive Sampling and Application of Downhole Sensor Technologies

Investigation of thermal convection in water columns using particle image velocimetry

An axisymmetric non-hydrostatic model for double-diffusive water systems

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