Microstructure and fluid flow in rift border fault-bounded basins – insights from the Dombjerg Fault, NE Greenland

In this contribution, we elucidate the interaction of structural deformation, fluid flow, and diagenesis in hanging wall siliciclastic deposits along rift basin-bounding faults, exemplified at the Dombjerg Fault in NE Greenland. Due to fault-controlled fluid circulation, fault-proximal syn-rift clastic deposits experienced pronounced calcite cementation and became lithified, whereas uncemented clastic deposits remained porous and friable. Correspondingly, two separate deformation regimes developed to accommodate continuous tectonic activity: discrete fractures formed in cemented deposits, and cataclastic deformation bands formed in uncemented deposits. We show that deformation bands act as partial baffles to fluid flow. This led to localized host rock alteration, which caused a chemical reduction of pore space along the bands. Where cemented, porosity was reduced towards zero and fracture formation created new pathways for fluid migration, which were subsequently filled with calcite. Occasionally, veins comprise multiple generations of microcrystalline calcite, which likely precipitated from an abruptly super-saturated fluid that was injected into the fracture. This suggests that cemented deposits sealed uncemented deposit bodies in which fluid overpressure was able to build up. We conclude that compartmentalized fluid flow regimes may form in rift fault-bounded basins, which has wide implications for assessments of potential carbon storage, hydrocarbon, groundwater, and geothermal sites.

Heat Transfer To Small Cylinders Within A Packed Bed

Heat transfer to small cylinders within a porous media has been experimentally and analytically studied extensively over a varying degree of sample and particle sizes and fluid flow regimes. In general, the observations, trends and empirical correlations developed for these systems do not accurately extrapolate down to small cylinders operating under the packed bed condition. The objective of this research is to develop an empirical correlation that expresses the Nusselt number of small cylinders immersed horizontally within a packed bed subject to forced convection heat transfer, in terms of the pertinent test parameters and material properties. Heat transfer to small cylinders within a porous media has been experimentally and analytically studied extensively over a varying degree of sample and particle sizes and fluid flow regimes. In general, the observations, trends and empirical correlations developed for these systems do not accurately extrapolate down to small cylinders operating under the packed bed condition. The objective of this research is to develop an empirical correlation that expresses the Nusselt number of small cylinders immersed horizontally within a packed bed subject to forced convection heat transfer, in terms of the pertinent test parameters and material properties.A set of seven small cylinders ranging in size from 1.27 to 9.53mm were resistively heated within a 311mm diameter lab-scale packed bed. The porous medium in which the samples were immersed was fine alumina oxide sand, with mean particle sizes ranging from 145 to 33μm. Four separate Type K thermocouples were used to measure temperatures at pertinent locations within the apparatus: bed temperature, inner sample temperature, left and right sample temperatures. The apparatus was operated under flow rates up until incipient fluidization. The trends observed in this research compared well with published data, though the correlations developed from other research consistently under-predicted the heat transfer capacity within the packed bed. The correlation that was developed for calculating the mean Nusselt number was accurate to within ±15% for the entire range of tested and published data.

Heat Transfer To Small Cylinders Within A Packed Bed

Heat transfer to small cylinders within a porous media has been experimentally and analytically studied extensively over a varying degree of sample and particle sizes and fluid flow regimes. In general, the observations, trends and empirical correlations developed for these systems do not accurately extrapolate down to small cylinders operating under the packed bed condition. The objective of this research is to develop an empirical correlation that expresses the Nusselt number of small cylinders immersed horizontally within a packed bed subject to forced convection heat transfer, in terms of the pertinent test parameters and material properties. Heat transfer to small cylinders within a porous media has been experimentally and analytically studied extensively over a varying degree of sample and particle sizes and fluid flow regimes. In general, the observations, trends and empirical correlations developed for these systems do not accurately extrapolate down to small cylinders operating under the packed bed condition. The objective of this research is to develop an empirical correlation that expresses the Nusselt number of small cylinders immersed horizontally within a packed bed subject to forced convection heat transfer, in terms of the pertinent test parameters and material properties.A set of seven small cylinders ranging in size from 1.27 to 9.53mm were resistively heated within a 311mm diameter lab-scale packed bed. The porous medium in which the samples were immersed was fine alumina oxide sand, with mean particle sizes ranging from 145 to 33μm. Four separate Type K thermocouples were used to measure temperatures at pertinent locations within the apparatus: bed temperature, inner sample temperature, left and right sample temperatures. The apparatus was operated under flow rates up until incipient fluidization. The trends observed in this research compared well with published data, though the correlations developed from other research consistently under-predicted the heat transfer capacity within the packed bed. The correlation that was developed for calculating the mean Nusselt number was accurate to within ±15% for the entire range of tested and published data.

From Early Contraction to Post-Folding Fluid Evolution in the Frontal Part of the Bóixols Thrust Sheet (Southern Pyrenees) as Revealed by the Texture and Geochemistry of Calcite Cements

Structural, petrological and geochemical (δ13C, δ18O, clumped isotopes, 87Sr/86Sr and ICP-MS) analyses of fracture-related calcite cements and host rocks are used to establish a fluid-flow evolution model for the frontal part of the Bóixols thrust sheet (Southern Pyrenees). Five fracture events associated with the growth of the thrust-related Bóixols anticline and Coll de Nargó syncline during the Alpine orogeny are distinguished. These fractures were cemented with four generations of calcite cements, revealing that such structures allowed the migration of different marine and meteoric fluids through time. During the early contraction stage, Lower Cretaceous seawater circulated and precipitated calcite cement Cc1, whereas during the main folding stage, the system opened to meteoric waters, which mixed with the connate seawater and precipitated calcite cement Cc2. Afterwards, during the post-folding stages, connate evaporated marine fluids circulated through newly formed NW-SE and NE-SW conjugate fractures and later through strike-slip faults and precipitated calcite cements Cc3 and Cc4. The overall paragenetic sequence reveals the progressive dewatering of Cretaceous marine host sediments during progressive burial, deformation and fold tightening and the input of meteoric waters only during the main folding stage. This study illustrates the changes of fracture systems and the associated fluid-flow regimes during the evolution of fault-associated folds during orogenic growth.

Go Fast With the Flow

This article discusses various applications of computational fluid dynamics (CFD) in the field of swimming. Using known physics and fluid dynamics relationships, CFD allows complex fluid flow regimes and geometry to be simulated within a computer environment. The ability to obtain segment-specific fluid force data within a full body stroking model provides enormous amounts of information that would be unobtainable via current empirical testing techniques. CFD software imports a realistic geometry of the athlete, generates the geometry of the surrounding water and air, and meshes these geometries to represent the athlete’s body in its surroundings. For world-class swimmers, the pursuit of a record-breaking performance at the 2016 Rio Olympics may well depend on CFD modeling and other simulations just as much as the athlete's physical ability. Experts see several applications for CFD, as engineers and academics continue their research into swimming, and coaches, athletes, and support teams prep for new competitions and championships, including the 2016 Rio Games. The growth of CFD methodology in swimming will rely on the ability to obtain easy and accurate 3-D kinematics.