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Subsurface Flow Physics Group
Towards energy and the environment
Dr. Bo Guo

Welcome

Welcome to the Subsurface Flow Physics Group at the University of Arizona. Our group is under the direction of Dr. Bo Guo, an assistant professor in the Department of Hydrology and Atmospheric Sciences and affiliated faculty of the Graduate Program in Applied Math. We study the fundamental physics of fluid flow and transport in Earth's subsurface. We develop and use novel mathematical and computational models to understand and quantify flow and transport processes in geological porous materials across a wide range of spatial scales from microscale (i.e., pore scale) to laboratory scale and to real-world subsurface environmental and energy problems at the field scale.

While we focus on computational modeling, we also frequently collaborate with experimentalists to utilize laboratory measured parameters and field data sets to drive the models and validate our predictions. Specific application areas of our research include contaminant transport in soil and groundwater especially emerging contaminants such as PFAS, shale gas/oil production, and geological CO2 sequestration. Our research is funded by National Science Foundation, Department of Defense, and American Chemical Society Petroleumn Research Fund.

Recent News


  • [April 18, 2024] Bo Guo starts to serve as Associate Editor of Water Resources Research.



  • [March 18, 2024] Two graduate students receive awards at the 2024 HAS annual El Dia student research symposium.

    Wenqian Zhang - Best Oral Presentation in Applied Subsurface Hydrology.
    Jake Smith - Outstanding Poster Presentation in Hydrogeology.

    See the full List of Awardees.



  • [February 28, 2024] PhD student Wenqian Zhang's paper "Anomalous adsorption of PFAS at the thin-water-film air–water interface in water-unsaturated porous media" has been published in Water Resources Research. [pdf]



  • [February 1, 2024] Master's student Jake Smith's paper "An integrated analytical modeling framework for determining site-specific soil screening levels for PFAS" has been published in Water Research. [pdf]



  • [January 11, 2024] Bo Guo gave a SERDP and ESTCP Webinar "PFAS-LEACH: A Comprehensive Decision Support Platform for Predicting PFAS Leaching in Source Zones" on our ESTCP Project ER21-5041. Recording of the talk on YouTube.



  • [December 19, 2023] We held a farewell party for two PhD students (Sidian Chen and Matt Bigler) leaving our group at The Moonstone Rooftop bar. Sidian will join Prof. Hamdi Tchelepi's group at Stanford University as a postdoc in January, 2024. Matt joined the Geosyntec Consultants earlier this year.



  • [December 18, 2023] Bo Guo receives the Humboldt Research Fellowship for Experienced Researchers, which will in part support his sabbatical leave at the University of Stuttgart from 2024-2025. See News at the University of Stuttgart.



  • [November 15, 2023] Bo Guo starts to serve as Associate Editor of Journal of Hydrology.



  • [August 13, 2023] Former PhD student Sidian Chen's paper "Pore-scale modeling of PFAS transport in water-unsaturated porous media: Air–water interfacial adsorption and mass-transfer processes in thin water films" has been published in Water Resources Research. [pdf]



  • [May 2, 2023] PhD student Sidian Chen successfully defended his PhD dissertation titled "Nonequilibrium Phenomena in Multiphase Flow, Transport, and Phase Change in Porous Media: Pore-Level Physics, Network Modeling and Upscaling." The committee members are: Bo Guo, Ty Ferre, Hoshin Gupta, Rainer Helmig (University of Stuttgart), and Jiamin Jiang (Chevron).



  • [April 23, 2023] Postdoc Jicai Zeng's paper "Reduced accessible air–water interfacial area accelerates PFAS leaching in heterogeneous vadose zones" has been published in Geophysical Research Letters. [pdf]



  • [March 20, 2023] A collaborative paper, co-authored by Mark Brusseau and Bo Guo, "Revising the EPA dilution-attenuation soil screening model for PFAS", has been published in Journal of Hazardous Materials Letters. [pdf]



  • [March 28, 2023] Four graduate students receive awards at the 2023 HAS annual El Dia student research symposium.

    Sidian Chen - Montgomery Outstanding Oral Presentation Award (highest award of the year).
    Mica Jarocki - Hydrology & Atmospheric Sciences Award of Excellence Poster Presentation.
    Jake Smith - Hydrology & Atmospheric Sciences Award of Excellence Poster Presentation.
    Ryan Russell - Stanley N. Davis Outstanding Poster Award.

    See the full List of Awardees.



  • [December 27, 2022] PhD student Jianwen Du wins one of the three student photo contest awards ($500) organized by the AGU Groundwater Technical Committee.



  • [December 21, 2022] Bo Guo receives the National Science Foundation CAREER Award.



  • [August 8, 2022] Two PhD students win scholarships from the Department of Hydrology and Atmospheric Sciences.

    Sidian Chen - John W. Harshbarger Memorial Endowment Scholarship.
    Wenqian Zhang - Shlomo and Yael Neuman Hydrology Endowment Scholarship.



  • [April 19, 2022] PhD student Sidian Chen wins the College of Science Scholarship Award . This prestigious award recognizes excellence in research and scholarship at the highest level among all graduate students in the College of Science.



  • [March 31, 2022] Bo Guo's paper on modeling of PFAS migration and retention in the vadose zone, in collaboration with Jicai Zeng (postdoc) and Mark Brusseau, has been recognized as a Top Cited Article in Water Resources Research from 2020-2021. [pdf]



  • [Jan 6, 2022] PhD student Sidian Chen starts a 6-month visit in Prof. Rainer Helmig's group at University of Stuttgart as part of the interdisciplinary Collaborative Research Centre SFB 1313



  • [Jan 3, 2022] Bo Guo's paper "A screening model for quantifying PFAS leaching in the vadose zone and mass discharge to groundwater", in collaboration with Jicai Zeng (postdoc), Mark Brusseau, and Yonggen Zhang, has been published in Advances in Water Resources. [pdf]



  • [November 11, 2021] Postdoc Jicai Zeng's paper "Model validation and analyses of parameter sensitivity and uncertainty for modeling long-term retention and leaching of PFAS in the vadose zone", in collaboration with Mark Brusseau, has been published in Journal of Hydrology. [pdf]



  • [August 24, 2021] PhD student Wenqian Zhang and MS student Mica Jarocki join the group.



  • [August 12, 2021] Postdoc Jicai Zeng's paper on assessing the impact of preferential and surfactant-induced flow on long-term PFAS leaching in heterogeneous vadose zones has been published in Advances in Water Resources. [pdf]



  • [August 10, 2021] Bo Guo is interviewed by ABC News on PFAS contamination in soils and groundwater. ABC News "'Ticking time bomb': PFAS chemicals in drinking water alarm scientists over health risks."



  • [July 20, 2021] Bo Guo's paper on modeling of PFAS migration and retention in the vadose zone, in collaboration with Jicai Zeng (postdoc) and Mark Brusseau, was among the Top 10% Most Downloaded Papers published in 2020 in Water Resources Research. [pdf]



  • [July 18, 2021] Our new ESTCP project was covered by UA News "UArizona Receives $1.3M Federal Grant to Study Synthetic Chemicals Posing Risk to Regional Aquifer" and KOLD News 13 "University of Arizona receives grant to study chemicals posing a threat to groundwater".



  • [June 28, 2021] Bo Guo receives the Doctoral New Investigator Award from American Chemical Society Petroleum Research Fund (ACS PRF).



  • [June 10, 2021] Bo Guo gave an invited talk "Compositional two-phase flow and nanoconfined phase behavior in shale rocks: pore-level physics, network modeling, and upscaling" at the international Geoscience and Geoenergy Webinar Series hosted by Prof. Hadi Hajibeygi (TU Delft) and Prof. Sebastian Geiger (Heriot-Watt University). Link to the recording of the talk on YouTube.



  • [April 8, 2021] PhD student Matt Bigler won third place in the virtual ENViSion student conference for his oral presentation "From the Surface to Our Groundwater: Understanding PFAS in firefighting foam and its link to groundwater contamination".



  • [April 5, 2021] PhD student Sidian Chen won the "Arizona Hydrological Society-Tucson Best Oral Award" at the 2021 virtual El Dia student conference and an "Outstanding Lightning Talk Award" at the Live Lightning Talk Competition among the six departments in the School of Earth and Environmental Sciences (SEES). Both events were an integral part of EarthWeek 2021.



  • [March 3, 2021] PhD student Sidian Chen's paper "A pore-network-based upscaling framework for the nanoconfined phase behavior in shale rocks", in collaboration with Jiamin Jiang from Chevron, has been published in Chemical Engineering Journal. [pdf]



  • [February 23, 2021] Bo Guo gave an invited talk entitled "Modeling CO2 injection and migration in deep saline aquifers: reduced-order, multiscale, and hybrid approaches" at KAUST's first online conference on "Enabling CO2 Geological Storage within a Low-Carbon Economy". Link to the KAUST conference agenda and zoom recordings.



  • [February 11, 2021] PhD student Sidian Chen receives the Outstanding Student Presentation Award (OSPA) from AGU 2020. The title of his talk was "Modeling the thermodynamic phase behavior of hydrocarbon mixtures in nanopores".



  • [October 30, 2020] Bo Guo gave an invited talk on mathematical modeling of PFAS transport and retention in the vadose zone at the Geological Society of America Annual Meeting [Session 255-T181 "Fate and Transport of PFAS in the Geologic Landscape"]. Link to the GSA press release of this session.



  • [October 26, 2020] PhD student Sidian Chen's paper on fully implicit dynamic pore-network modeling of two-phase flow and phase change in porous media, in collaboration with Chaozhong Qin from Chongqing University, has been published in Water Resources Research. [pdf]



  • [August 13, 2020] PhD student Sidian Chen wins the "John W. Harshbarger Memorial Endowment" Scholarship from the Department of Hydrology and Atmospheric Sciences.



  • [April 21, 2020] PhD student Sidian Chen wins the Geosystems Analysis, Inc. Best Virtual Poster Award at the 2020 virtual El Dia student conference.



  • [February 7, 2020] Bo Guo's paper on modeling of PFAS migration and retention in the vadose zone, in collaboration with Jicai Zeng (postdoc) and Mark Brusseau, has been published in Water Resources Research. [pdf].
    • *News coverage: UA News, Phys.org, AAAS EurekAlert, ScienceDaily, The Medical News, Technology Networks, Futurity, Chem Europe, Scitech Daily, Electronics360.