[{"content":"We are a research group focused on understanding the mechanics of granular and multiphase fluid systems. We develop simulation tools that resolve pore-scale fluid physics and grain-scale solid mechanics, under mechanical, hydraulic, and thermal loading conditions. Our goal is to build fundamental understanding of granular-fluid systems, under complex conditions where current models and experiments fall short, to better predict their macroscopic behavior for emerging engineering applications.\n","externalUrl":null,"permalink":"/","section":"","summary":"We are a research group focused on understanding the mechanics of granular and multiphase fluid systems. We develop simulation tools that resolve pore-scale fluid physics and grain-scale solid mechanics, under mechanical, hydraulic, and thermal loading conditions. Our goal is to build fundamental understanding of granular-fluid systems, under complex conditions where current models and experiments fall short, to better predict their macroscopic behavior for emerging engineering applications.\n","title":"","type":"page"},{"content":"","externalUrl":null,"permalink":"/categories/","section":"Categories","summary":"","title":"Categories","type":"categories"},{"content":" Open Position: Postdoctoral Researcher in Scientific Computing and GPU Acceleration # We are seeking a postdoctoral researcher to join ConGloMeRaTe at Virginia Tech (Blacksburg, VA) for a one-year position focused on GPU acceleration of LBMphaseX, our in-house lattice Boltzmann simulation framework. The primary goal of this position is to implement and optimize GPU computing capabilities for LBMphaseX to enable large-scale pore-scale simulations of granular and multiphase fluid systems. LBMphaseX is an established, modular, and actively developed codebase, and the successful candidate will focus primarily on GPU acceleration, optimization, and performance improvement rather than model development.\nThis position is ideal for a researcher with a strong computational background who wants to apply their expertise to challenging engineering problems and broaden their research profile. The successful candidate will work closely with the research team and will have opportunities to co-author publications resulting from the accelerated framework and the simulations it enables.\nQualifications\nA PhD in computational science, computer science, computational physics, applied mathematics, engineering, or a related field Strong expertise in GPU computing and CUDA-based parallelization Strong C++ programming skills and experience working with large scientific software projects Experience optimizing and profiling high-performance simulation codes Experience with HPC environments and parallel programming (e.g., MPI, OpenMP) is desirable Familiarity with lattice Boltzmann methods or other numerical simulation methods is a plus, but not required Appointment\nThe position is available immediately and is funded for one year, with the possibility of extension depending on funding availability.\nSalary: $60,000–$65,000 per year plus benefits.\nApplication Instructions\nTo apply, please send an email to reihos@vt.edu with the subject line \u0026ldquo;Postdoc Application\u0026rdquo; and include your CV and a brief description of your GPU programming experience. Applications will be reviewed on a rolling basis until the position is filled.\nPhD Students # We do not have funded PhD positions available at the moment. However, if you believe your background and interests align well with our research, you are welcome to reach out. We will keep strong candidates on file and contact them as funded positions become available.\nQualifications\nBackground in civil or geotechnical engineering Familiarity with numerical methods or scientific computing Prior coding experience Curiosity, independence, and a genuine interest in understanding the physics behind engineering problems Application Instructions\nPlease send an email to reihos@vt.edu with the subject line \u0026ldquo;Prospective PhD Student\u0026rdquo; and include your CV and a brief description of your background and why ConGloMeRaTe would be a good fit for you. Generic inquiry emails are unlikely to receive a response.\n","externalUrl":null,"permalink":"/join/","section":"Join Us","summary":"Open Position: Postdoctoral Researcher in Scientific Computing and GPU Acceleration # We are seeking a postdoctoral researcher to join ConGloMeRaTe at Virginia Tech (Blacksburg, VA) for a one-year position focused on GPU acceleration of LBMphaseX, our in-house lattice Boltzmann simulation framework. The primary goal of this position is to implement and optimize GPU computing capabilities for LBMphaseX to enable large-scale pore-scale simulations of granular and multiphase fluid systems. LBMphaseX is an established, modular, and actively developed codebase, and the successful candidate will focus primarily on GPU acceleration, optimization, and performance improvement rather than model development.\n","title":"Join Us","type":"join"},{"content":" Principal Investigator Reihaneh Hosseini Reihaneh is a Research Assistant Professor in the geotechnical group in the Department of Civil and Environmental Engineering at Virginia Tech. She received her PhD (2022) and MS (2018) in civil engineering from the University of Texas at Austin and her BS (2016) in civil engineering from the University of Tehran. Her research focuses on grain-scale and pore-scale computational modeling of granular and multiphase fluid systems, with current applications centered on the behavior of geomaterials under complex environmental conditions, such as unsaturated and frozen states, and the implications of these conditions for geohazards and infrastructure performance. Her long-term vision is to build a research program that is highly specialized in modeling capability yet broad in scientific reach, addressing fundamental questions about granular and porous multiphase materials across geomechanics, materials science, planetary science, and beyond.\nPhD Students Sina Sadeghi Sina is a PhD student in the geotechnical group in the Department of Civil and Environmental Engineering at Virginia Tech. He received his MS (2021) and BS (2018) in civil engineering from the University of Tehran. Before joining Virginia Tech, he worked as a software developer and structural designer at StructurePlus, where he developed software for structural optimization. His research focuses on pore-scale numerical modeling of the cone penetration test (CPT) in granular soils, with particular emphasis on capturing drainage behavior and the role of fluid-solid coupling on penetration resistance. He plans to extend this work to unsaturated conditions, motivated by the real-world risk of misinterpreting CPT measurements in tailings deposits where partial saturation can mask low densities and lead to catastrophic failure upon saturation.\nProject: Grain- and Pore-Scale Mechanics of Cone Penetration in Granular Soils | Member since: Spring 2024 Clara Toffoli Clara is a PhD student in the geotechnical group in the Institute of Geotechnics and Construction Management at the Hamburg University of Technology (TUHH), Germany. She received her MS (2021) in geotechnics and her BS (2018) in civil engineering from the University of Brasilia, Brazil. Her current research focuses on pore-scale numerical modeling of multiphase granular material, with focus on understanding effective stresses in such materials. Her previous research includes mining topics and also synchrotron computed tomography of granular materials. Between her MS and PhD, she worked for 1.5 years in a mining consulting company in Belo Horizonte, Brazil, focusing on design and maintenance of tailing dams, dry-stacked tailings and open pit mines.\nProject: Micromechanical Behavior of Unsaturated Granular Soils | Member since: Fall 2023 Behrooz Daneshian Behrooz is a PhD student in the geotechnical group in the Department of Civil and Environmental Engineering at Virginia Tech. He received his MS (2016) and BS (2012) degrees in civil engineering from Shiraz University. His research focuses on pore-scale numerical simulation of freezing and thawing processes in saturated and unsaturated granular soils. He has developed a numerical framework capable of simulating pore-scale freezing and thawing behavior in saturated soils. He plans to further extend the framework to model freezing processes in unsaturated soils. This extension aims to improve the understanding of poorly studied pore-scale mechanisms, including the complex interactions among air, water, and ice, as well as cryogenic suction during freezing.\nProject: Pore-Scale Freezing Mechanisms in Saturated and Unsaturated Soils | Member since: Fall 2023 ","externalUrl":null,"permalink":"/members/","section":"","summary":" Principal Investigator Reihaneh Hosseini Reihaneh is a Research Assistant Professor in the geotechnical group in the Department of Civil and Environmental Engineering at Virginia Tech. She received her PhD (2022) and MS (2018) in civil engineering from the University of Texas at Austin and her BS (2016) in civil engineering from the University of Tehran. Her research focuses on grain-scale and pore-scale computational modeling of granular and multiphase fluid systems, with current applications centered on the behavior of geomaterials under complex environmental conditions, such as unsaturated and frozen states, and the implications of these conditions for geohazards and infrastructure performance. Her long-term vision is to build a research program that is highly specialized in modeling capability yet broad in scientific reach, addressing fundamental questions about granular and porous multiphase materials across geomechanics, materials science, planetary science, and beyond.\n","title":"Members","type":"page"},{"content":"Journal Articles Toffoli, C. M., Hosseini, R., \u0026amp; Grabe, J. (2026). Comparison of the three main multifluid extensions of the lattice Boltzmann method used for modeling unsaturated soils. Computers and Geotechnics, 196, 108192. https://doi.org/10.1016/j.compgeo.2026.108192\nHosseini, R., \u0026amp; Kumar, K. (2025). Micromechanical evaluation of the effective stress parameter using the multiphase lattice Boltzmann method and investigation of its hysteresis. Computers and Geotechnics, 188, 107564. https://doi.org/10.1016/j.compgeo.2025.107564\nHosseini, R., Kumar, K., \u0026amp; Delenne, J.-Y. (2024). Investigating the source of hysteresis in the soil–water characteristic curve using the multiphase lattice Boltzmann method. Acta Geotechnica. https://doi.org/10.1007/s11440-024-02295-y\nconference papers Toffoli, C. M., Hosseini, R., \u0026amp; Grabe, J. (2026). A 3D-printed physical model of a 2D granular packing for experimental validation of multifluid LBM Simulations. 11th International Conference on Physical Modelling in Geotechnics (ICPMG 2026).\nDaneshian, B., Hosseini, R., \u0026amp; Abdelaziz, S. L. (2025). Predicting the Pore Size Distribution of Saturated Clay at Different Temperatures Using Pore Network Analysis. Geotechnical Frontiers 2025, 221–230. https://doi.org/10.1061/9780784485989.023\nabstracts and oral presentations Hosseini, R., Toffoli, C. M., \u0026amp; Grabe, J. (2026). Choosing the appropriate multiphase lattice Boltzmann approach for simulating pore-scale fluid distributions in unsaturated granular soils. Engineering Mechanics Institute Conference (EMI 2026). Boulder, Colorado, June 2-5, 2026.\nSadeghi, S., Hosseini, R. (2026). Modeling the Cone Penetration Test in Saturated Granular Soils Using Coupled LBM–DEM: Challenges and Capabilities. Engineering Mechanics Institute Conference. Engineering Mechanics Institute Conference (EMI 2026). Boulder, Colorado, June 2-5, 2026.\nToffoli, C. M., Hosseini, R., \u0026amp; Grabe, J. (2024). Comparison of three different multiphase LBM strategies for numerically obtaining the soil water retention curve of granular materials. Engineering Mechanics Institute 2024 International Conference (EMI 2024 IC). Vienna, Austria, September 11-13, 2024.\n","externalUrl":null,"permalink":"/publications/","section":"Publications","summary":"Journal Articles Toffoli, C. M., Hosseini, R., \u0026 Grabe, J. (2026). Comparison of the three main multifluid extensions of the lattice Boltzmann method used for modeling unsaturated soils. Computers and Geotechnics, 196, 108192. https://doi.org/10.1016/j.compgeo.2026.108192\nHosseini, R., \u0026 Kumar, K. (2025). Micromechanical evaluation of the effective stress parameter using the multiphase lattice Boltzmann method and investigation of its hysteresis. Computers and Geotechnics, 188, 107564. https://doi.org/10.1016/j.compgeo.2025.107564\nHosseini, R., Kumar, K., \u0026 Delenne, J.-Y. (2024). Investigating the source of hysteresis in the soil–water characteristic curve using the multiphase lattice Boltzmann method. Acta Geotechnica. https://doi.org/10.1007/s11440-024-02295-y\n","title":"Publications","type":"publications"},{"content":" The projects below reflect our current research efforts to advance understanding of granular and multiphase systems under various conditions. Grain- and Pore-Scale Mechanics of Cone Penetration in Granular Soils Coupled LBM-DEM simulation of cone penetration in a saturated granular soil. The cone penetration test (CPT) is one of the most widely used tools for in situ characterization of soils, providing continuous measurements of penetration resistance that are used to infer geotechnical soil properties. However, CPT interpretation becomes significantly less reliable under non-standard conditions such as partial drainage or partial saturation, where existing correlations break down and the assumptions underlying conventional interpretation no longer hold. This project uses coupled lattice Boltzmann method and discrete element method (LBM-DEM) simulations to model CPT at the pore scale, directly resolving the interaction between grain motion and pore fluid during penetration. The goal is to build a mechanistic understanding of how drainage conditions and fluid phases influence penetration resistance and pore pressure response, with implications for more reliable CPT interpretation in complex field conditions.\nSponsor: Virginia Tech Micromechanical Behavior of Unsaturated Granular Soils Comparison of drainage in a 2D porous medium as predicted by different LBM multifluid approaches (multiphase Shan–Chen, multicomponent Shan–Chen, and He–Chen–Zhang) and a physical model. Most soils in nature exist in an unsaturated state, with both water and air occupying the pore space between grains. The distribution of these fluid phases within the pore space gives rise to capillary forces between grains that affect soil stiffness and shear strength in ways that current engineering models capture only empirically, without a full mechanistic understanding of the underlying pore-scale physics. This project uses coupled multiphase LBM-DEM simulations to directly visualize and quantify how fluid distributions and capillary forces evolve at the grain scale under varying saturation conditions. Resolving the full three-phase interaction between water, air, and soil grains enables systematic investigation of how pore-scale processes influence the mechanical and hydraulic response of unsaturated soils, which can ultimately inform more reliable constitutive models for engineering practice.\nSponsor: German Research Foundation (DFG) Pore-Scale Freezing Mechanisms in Saturated and Unsaturated Soils LBM simulation of top-down freezing of an unsaturated soil sample. Frozen ground covers more than half of the Earth's land surface, and its mechanical behavior governs the performance of infrastructure in cold regions, from roads and pipelines to military installations in arctic environments. The thermo-hydro-mechanical behavior of freezing soils is fundamentally controlled by pore-scale processes: the distribution of ice, water, and air within the pore space, and how that distribution evolves as temperature drops. These processes are difficult to observe experimentally, leaving key mechanisms such as ice nucleation, cryogenic suction, and phase redistribution in unsaturated soils poorly understood. This project develops a pore-scale numerical framework coupling thermal LBM with multiphase LBM to simulate freezing in both saturated and unsaturated granular soils. By directly resolving phase evolution within complex pore geometries, the goal is to uncover the grain-scale mechanisms that govern frozen soil behavior and provide a foundation for more reliable predictive models in cold-region geotechnical engineering.\nSponsor: Cold Regions Research and Engineering Laboratory (ERDC-CRREL) ","externalUrl":null,"permalink":"/research/","section":"Research","summary":" The projects below reflect our current research efforts to advance understanding of granular and multiphase systems under various conditions. Grain- and Pore-Scale Mechanics of Cone Penetration in Granular Soils Coupled LBM-DEM simulation of cone penetration in a saturated granular soil. The cone penetration test (CPT) is one of the most widely used tools for in situ characterization of soils, providing continuous measurements of penetration resistance that are used to infer geotechnical soil properties. However, CPT interpretation becomes significantly less reliable under non-standard conditions such as partial drainage or partial saturation, where existing correlations break down and the assumptions underlying conventional interpretation no longer hold. This project uses coupled lattice Boltzmann method and discrete element method (LBM-DEM) simulations to model CPT at the pore scale, directly resolving the interaction between grain motion and pore fluid during penetration. The goal is to build a mechanistic understanding of how drainage conditions and fluid phases influence penetration resistance and pore pressure response, with implications for more reliable CPT interpretation in complex field conditions.\n","title":"Research","type":"research"},{"content":" LBMphaseX # ConGloMeRaTe is currently developing LBMphaseX, an in-house pore-scale simulation framework based on the lattice Boltzmann method (LBM) for modeling coupled fluid, thermal, and granular processes. Current capabilities include:\nMultiple multiphase LBM formulations for simulating complex fluid-fluid and fluid-solid interactions within pore structures. Thermal LBM for modeling heat transfer and phase change processes. Coupling with the open-source discrete element method (DEM) software Yade for both single-phase and multiphase flow conditions. Parallel implementation supporting high-performance computing environments. LBMphaseX is not yet publicly available. It will be released as open-source software upon full development.\n","externalUrl":null,"permalink":"/software/","section":"Software","summary":"LBMphaseX # ConGloMeRaTe is currently developing LBMphaseX, an in-house pore-scale simulation framework based on the lattice Boltzmann method (LBM) for modeling coupled fluid, thermal, and granular processes. Current capabilities include:\nMultiple multiphase LBM formulations for simulating complex fluid-fluid and fluid-solid interactions within pore structures. Thermal LBM for modeling heat transfer and phase change processes. Coupling with the open-source discrete element method (DEM) software Yade for both single-phase and multiphase flow conditions. Parallel implementation supporting high-performance computing environments. LBMphaseX is not yet publicly available. It will be released as open-source software upon full development.\n","title":"Software","type":"software"},{"content":"","externalUrl":null,"permalink":"/tags/","section":"Tags","summary":"","title":"Tags","type":"tags"}]