he Discrete Element Method (DEM) has gained significant popularity as a technique for simulating granular flows. However, its high computational cost has remained a primary limitation for decades. This limitation hinders its application in simulating realistic large-scale industrial scenarios. The Coarse Graining (CG) method addresses this issue by substituting physical particles with up-scaled particles, commonly referred to as parcels. Among CG techniques, the Same Size Parcel (SSP) approach is considered the most efficient, as it achieves the greatest reduction of constituents in poly-disperse media. Nevertheless, SSP is unable to simulate size-driven phenomena, such as segregation, which significantly restricts its applicability to systems with size heterogeneity. In this context, the present article introduces a novel local model that captures size-driven segregation during Coarse Grained - Same Size Parcel (CG-SSP) simulations when in dense regime. Preliminary results from flowing chute modeling indicate highly promising outcomes, suggesting a potential advancement towards the rapid simulation of poly-disperse, large-scale particle flows.
Fairy circles are natural circular surface depressions devoid of vegetation that are widely distributed on the Earth's surface. These distinctive formations have only recently been associated with natural hydrogen production within their perimeter. Although they are the object of keen interest by scientists in search of clean energy sources, little is known about the origin of the gas and the formation of these fairy circles. In this paper, gas seepage from an underground point source through a saturated porous medium is studied numerically to explore its potential implications for identifying new energy resources. It is shown that, with the hypotheses adopted in the simulations, the formation of a surface depression could not be predicted in the framework of Biot theory of poroelasticity alone. However, the addition of a mechanism of volumetric compaction associated with the presence of gas in the numerical model could be used to match InSAR data collected in the field.
This study presents numerical simulations of the August-September 2024 circulation test conducted at the Utah FORGE site, an Enhanced Geothermal System (EGS) project. The one-month circulation test followed a hydraulic stimulation campaign, aiming to assess fluid flow and heat transfer within the fractured reservoir. The circulation test was performed between an injection and a production well, with flow pathways identified using fiber optic sensing, microseismicity, and spinner test data. The numerical simulations were conducted using XSiteTM, a Thermal-Hydro-Mechanical (THM) modeling tool, to history match field observations. The model incorporated key reservoir characteristics, including fracture geometry, aperture sizes, and flow distributions derived from test data. Simulation results closely aligned with field data, capturing temperature trends, though minor discrepancies were noted due to natural fracture complexities. This work contributes to improved predictive capabilities for EGS performance and provides insights into optimizing geothermal resource development.
