Littérature scientifique sur le sujet « Numerical model, faults, rheology »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les listes thématiques d’articles de revues, de livres, de thèses, de rapports de conférences et d’autres sources académiques sur le sujet « Numerical model, faults, rheology ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Articles de revues sur le sujet "Numerical model, faults, rheology"
1
Saxena, Arushi, Eunseo Choi, Christine A. Powell et Khurram S. Aslam. « Seismicity in the central and southeastern United States due to upper mantle heterogeneities ». Geophysical Journal International 225, no 3 (10 mars 2021) : 1624–36. http://dx.doi.org/10.1093/gji/ggab051.
Texte intégralRésumé :
SUMMARY Sources of stress responsible for earthquakes occurring in the Central and Eastern United States (CEUS) include not only far-field plate boundary forces but also various local contributions. In this study, we model stress fields due to heterogeneities in the upper mantle beneath the CEUS including a high-velocity feature identified as a lithospheric drip in a recent regional P-wave tomography study. We calculate velocity and stress distributions from numerical models for instantaneous 3-D mantle flow. Our models are driven by the heterogeneous density distribution based on a temperature field converted from the tomography study. The temperature field is utilized in a composite rheology, assumed for the numerical models. We compute several geodynamic quantities with our numerical models: dynamic topography, rate of dynamic topography, gravitational potential energy (GPE), differential stress, and Coulomb stress. We find that the GPE, representative of the density anomalies in the lithosphere, is an important factor for understanding the seismicity of the CEUS. When only the upper mantle heterogeneities are included in a model, differential and Coulomb stress for the observed fault geometries in the CEUS seismic zones acts as a good indicator to predict the seismicity distribution. Our modelling results suggest that the upper mantle heterogeneities and structure below the CEUS have stress concentration effects and are likely to promote earthquake generation at preexisting faults in the region’s seismic zones. Our results imply that the mantle flow due to the upper-mantle heterogeneities can cause stress perturbations, which could help explain the intraplate seismicity in this region.
2
Moore, Peter L., Neal R. Iverson et Denis Cohen. « Ice flow across a warm-based/cold-based transition at a glacier margin ». Annals of Glaciology 50, no 52 (2009) : 1–8. http://dx.doi.org/10.3189/172756409789624319.
Texte intégralRésumé :
AbstractWhere polythermal glaciers have frozen margins that buttress otherwise temperate-based sliding ice, longitudinal compression can strongly influence ice-flow trajectory, and consequently sediment transport paths. Past efforts to model flow in the vicinity of a basal thermal transition (BTT) have generally relied on simplified boundary conditions or rheological idealizations, making these model results difficult to apply to real glacier termini. Herein, we present results of numerical simulations using a power-law rheology and with boundary conditions that better represent the frozen margin. Model results indicate that a transition to a non-sliding frozen margin causes a decline in surface velocity made possible by upward ice flow, implying either enhanced ablation for steady-state simulations or the formation of a surface bulge. Permitting ice loss by ablation combined with numerical smoothing of the basal slip transition subdues basal stress concentrations and thereby inhibits development of structural discontinuities such as thrust faults. Upward ice flow is accommodated by vertical extension up-glacier of the BTT. This strain regime can potentially account for key structural features in polythermal glacier termini without appealing to thrusting.
3
Preuss, Simon, Jean Paul Ampuero, Taras Gerya et Ylona van Dinther. « Characteristics of earthquake ruptures and dynamic off-fault deformation on propagating faults ». Solid Earth 11, no 4 (22 juillet 2020) : 1333–60. http://dx.doi.org/10.5194/se-11-1333-2020.
Texte intégralRésumé :
Abstract. Natural fault networks are geometrically complex systems that evolve through time. The evolution of faults and their off-fault damage patterns are influenced by both dynamic earthquake ruptures and aseismic deformation in the interseismic period. To better understand each of their contributions to faulting we simulate both earthquake rupture dynamics and long-term deformation in a visco-elasto-plastic crust subjected to rate- and state-dependent friction. The continuum mechanics-based numerical model presented here includes three new features. First, a 2.5-D approximation is created to incorporate the effects of a viscoelastic lower crustal substrate below a finite depth. Second, we introduce a dynamically adaptive (slip-velocity-dependent) measure of fault width to ensure grid size convergence of fault angles for evolving faults. Third, fault localization is facilitated by plastic strain weakening of bulk rate and state friction parameters as inspired by laboratory experiments. This allows us to simulate sequences of episodic fault growth due to earthquakes and aseismic creep for the first time. Localized fault growth is simulated for four bulk rheologies ranging from persistent velocity weakening to velocity strengthening. Interestingly, in each of these bulk rheologies, faults predominantly localize and grow due to aseismic deformation. Yet, cyclic fault growth at more realistic growth rates is obtained for a bulk rheology that transitions from velocity-strengthening friction to velocity-weakening friction. Fault growth occurs under Riedel and conjugate angles and transitions towards wing cracks. Off-fault deformation, both distributed and localized, is typically formed during dynamic earthquake ruptures. Simulated off-fault deformation structures range from fan-shaped distributed deformation to localized splay faults. We observe that the fault-normal width of the outer damage zone saturates with increasing fault length due to the finite depth of the seismogenic zone. We also observe that dynamically and statically evolving stress fields from neighboring fault strands affect primary and secondary fault growth and thus that normal stress variations affect earthquake sequences. Finally, we find that the amount of off-fault deformation distinctly depends on the degree of optimality of a fault with respect to the prevailing but dynamically changing stress field. Typically, we simulate off-fault deformation on faults parallel to the loading direction. This produces a 6.5-fold higher off-fault energy dissipation than on an optimally oriented fault, which in turn has a 1.5-fold larger stress drop. The misalignment of the fault with respect to the static stress field thus facilitates off-fault deformation. These results imply that fault geometries bend, individual fault strands interact, and optimal orientations and off-fault deformation vary through space and time. With our work we establish the basis for simulations and analyses of complex evolving fault networks subject to both long-term and short-term dynamics.
4
Le Pourhiet, L., B. Huet, L. Labrousse, K. Yao, P. Agard et L. Jolivet. « Strain localisation in mechanically layered rocks beneath detachment zones : insights from numerical modelling ». Solid Earth 4, no 1 (17 avril 2013) : 135–52. http://dx.doi.org/10.5194/se-4-135-2013.
Texte intégralRésumé :
Abstract. We have designed a series of fully dynamic numerical simulations aimed at assessing how the orientation of mechanical layering in rocks controls the orientation of shear bands and the depth of penetration of strain in the footwall of detachment zones. Two parametric studies are presented. In the first one, the influence of stratification orientation on the occurrence and mode of strain localisation is tested by varying initial dip of inherited layering in the footwall with regard to the orientation of simple shear applied at the rigid boundary simulating a rigid hanging wall, all scaling and rheological parameter kept constant. It appears that when Mohr–Coulomb plasticity is being used, shear bands are found to localise only when the layering is being stretched. This corresponds to early deformational stages for inital layering dipping in the same direction as the shear is applied, and to later stages for intial layering dipping towards the opposite direction of shear. In all the cases, localisation of the strain after only γ=1 requires plastic yielding to be activated in the strong layer. The second parametric study shows that results are length-scale independent and that orientation of shear bands is not sensitive to the viscosity contrast or the strain rate. However, decreasing or increasing strain rate is shown to reduce the capacity of the shear zone to localise strain. In the later case, the strain pattern resembles a mylonitic band but the rheology is shown to be effectively linear. Based on the results, a conceptual model for strain localisation under detachment faults is presented. In the early stages, strain localisation occurs at slow rates by viscous shear instabilities but as the layered media is exhumed, the temperature drops and the strong layers start yielding plastically, forming shear bands and localising strain at the top of the shear zone. Once strain localisation has occured, the deformation in the shear band becomes extremely penetrative but the strength cannot drop since the shear zone has a finite thickness.
5
Andrea Bizzarri, Alberto Petri et Andrea Baldassarri. « Earthquake dynamics constrained from laboratory experiments : new insights from granular materials ». Annals of Geophysics 64, no 4 (16 novembre 2021) : SE441. http://dx.doi.org/10.4401/ag-8613.
Texte intégralRésumé :
The traction evolution is a fundamental ingredient to model the dynamics of an earthquake rupture which ultimately controls, during the coseismic phase, the energy release, the stress redistribution and the consequent excitation of seismic waves. In the present paper we explore the use of the friction behavior derived from laboratory shear experiments performed on granular materials at low normal stress. We find that the rheological properties emerging from these laboratory experiments can not be described in terms of preexisting governing models already presented in literature; our results indicate that neither rate–and state–dependent friction laws nor nonlinear slip–dependent models, commonly adopted for modeling earthquake ruptures, are able to capture all the features of the experimental data. Then, by exploiting a novel numerical approach, we directly incorporate the laboratory data into a code to simulate the fully dynamic propagation of a 3–D slip failure. We demonstrate that the rheology of the granular material, imposed as fault boundary condition, is dynamically consistent. Indeed, it is able to reproduce the basic features of a crustal earthquake, spontaneously accelerating up to some terminal rupture speed, both sub– and supershear.
6
Finzi, Yaron, Elizabeth H. Hearn, Yehuda Ben-Zion et Vladimir Lyakhovsky. « Structural Properties and Deformation Patterns of Evolving Strike-slip Faults : Numerical Simulations Incorporating Damage Rheology ». Pure and Applied Geophysics 166, no 10-11 (30 juin 2009) : 1537–73. http://dx.doi.org/10.1007/s00024-009-0522-1.
Texte intégral
7
Seol, D. E., et C. G. Kang. « Numerical Analysis of Two-Phase Thermal Flow for Rheology Forging Process ». Solid State Phenomena 116-117 (octobre 2006) : 673–76. http://dx.doi.org/10.4028/www.scientific.net/ssp.116-117.673.
Texte intégralRésumé :
The algorithm two-phase flow model, developed in this study, gives die filling patterns, velocity, temperature and solid fraction of rheology material during rheology forging process. To calculate the velocity and temperature fields, the respective governing equations corresponding to the liquid and solid region were adapted. Therefore, respective numerical models considering the solid and liquid phase co-existent within the rheology material have been developed to predict the defects of part manufactured by the rheology forging process. This study has focused on the simulation of the rheology forging process and calculation of the velocity profiles and temperature distribution. And, to predict the liquid segregation in the part, the deviation of velocity between liquid and solid region in the two-phase flow model was analysed.
8
Zhang, De-Han. « Numerical analysis model of horizontal displacement of active faults ». Acta Seismologica Sinica 6, no 3 (août 1993) : 601–8. http://dx.doi.org/10.1007/bf02650399.
Texte intégral
9
Chen, Ge, Xiao Cong Ren et Xiao Zheng. « Numerical Simulation of Flaxseed and Cottonseed Oil Cakes ». Applied Mechanics and Materials 687-691 (novembre 2014) : 631–36. http://dx.doi.org/10.4028/www.scientific.net/amm.687-691.631.
Texte intégralRésumé :
The pressed oil-extraction process is essentially a process of oil seepage through porous cake-shaped media. Permeability of seepage field changes along with the change of porous media caused by press pressure. The change of permeability affects fluid pressure and effective pressure of oil cake pores, which means that porosity is influenced. On the contrary, the change of porosity also has an impact on permeability. The interaction between the seepage and rheology fields is termed as fluid-solid coupling. If rheology of oil cakes is considered, the fluid-solid coupling seepage with the rheological properties is the essence of the pressed oil-extraction process. In the present study, we studied a permeability model based on the deformable and rheological properties of oilseed cakes and the effective stress. The seepage and rheology fields were analyzed by alternative application of the finite difference and finite element methods. The finite element calculation model of nonlinear rheology field was established by the time step-initial strain method. We used flax and cotton seeds as examples to perform numerical simulation and calculate the displacement and pore fluid pressure dissipation of flaxseed and cottonseed oil during the press process.
10
Gallo-Molina, Juan Pablo, Karel Lesage et Ingmar Nopens. « Numerical Validation of a Population Balance Model Describing Cement Paste Rheology ». Materials 13, no 5 (10 mars 2020) : 1249. http://dx.doi.org/10.3390/ma13051249.
Texte intégralRésumé :
Rheology control is essential during the period in which cement and concrete pastes are encountered in the fresh state, due to the fact that it directly affects workability, initial placement and the structural performance of the hardened material. Optimizations of clinker formulations and reductions in cement-to-water ratios induced by economic and environmental considerations have a significant effect in rheology, which invokes the need for mechanistic models capable of describing the effect of multiple relevant phenomena on the observed paste flow. In this work, the population balance framework was implemented to develop a model able to relate the transient microstructural evolution of cement pastes under typical experimental conditions with its macroscopic rheological responses. Numerical details and performance are assessed and discussed. It was found that the model is capable of reproducing experimentally observed flow curves by using measured cluster size distribution information. It is also able to predict the complex rheological characteristics typically found in cement pastes. Furthermore, a spatially resolved scheme was proposed to investigate the nature of flow inside a parallel-plates rheometer geometry with the objective of assessing the ability of the model of qualitatively predicting experimentally observed behavior and to gain insight into the effect of possible secondary flows.
Thèses sur le sujet "Numerical model, faults, rheology"
1
Bai, Zhuofu. « LOCALIZING FAULTS IN NUMERICAL SOFTWARE USING A VALUE-BASED CAUSAL MODEL ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459437802.
Texte intégral
2
Lee, Hisung. « A numerical solution to the elastohydrodynamic problem incorporating a non-newtonian rheological model ». Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/15945.
Texte intégral
3
Vasilic, Ksenija. « A Numerical Model for Self-Compacting Concrete Flow through Reinforced Sections : a Porous Medium Analogy ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-194402.
Texte intégralRésumé :
This thesis addresses numerical simulations of self-compacting concrete (SCC) castings and suggests a novel modelling approach that treats reinforcement zones in a formwork as porous media. As a relatively new field in concrete technology, numerical simulations of fresh concrete flow can be a promising aid to optimise casting processes and to avoid on-site casting incidents by predicting the flow behaviour of concrete during the casting process. The simulations of fresh concrete flow generally involve complex mathematical modelling and time-consuming computations. In case of a casting prediction, the simulation time is additionally significantly increased because each reinforcement bar occurring in succession has to be considered one by one. This is particularly problematic when simulating SCC casting, since this type of concrete is typically used for heavily reinforced structural members. However, the wide use of numerical tools for casting prediction in practice is possible only if the tools are user-friendly and simulations are time-saving. In order to shorten simulation time and to come closer to a practical tool for casting prediction, instead to model steel bars one by one, this thesis suggests to model zones with arrays of steel bars as porous media. Consequently, one models the flow of SCC through a reinforcement zone as a free-surface flow of a non-Newtonian fluid, propagating through the medium. By defining characteristic parameters of the porous medium, the influence on the flow and the changed (apparent) behaviour of concrete in the porous matrix can be predicted. This enables modelling of any reinforcement network as a porous zone and thus significantly simplifies and fastens simulations of reinforced components’ castings. Within the thesis, a computational model for SCC flow through reinforced sections was developed. This model couples a fluid dynamics model for fresh concrete and the macroscopic approach for the influence of the porous medium (formed by the rebars) on the flow. The model is implemented into a Computational Fluid Dynamics software and validated on numerical and experimental studies, among which is a large-scale laboratory casting of a highly reinforced beam. The apparent rheology of concrete within the arrays of steel bars is studied and a methodology to determine unknown input parameters for the porous medium is suggested. Normative tables defining characteristic porous medium parameters as a function of the topology of the rebar zone for different reinforcement cases are generated. Finally, the major contribution of this work is the resulting numerical package, consisting of the numerical solver and the parameter library. The thesis concludes on the ability of the porous medium analogy technique to reliably predict the concrete casting behaviour, while being significantly easier to use and far less time consuming than existing toolsDie Arbeit behandelt die numerische Modellierung des Fließverhaltens von selbst-verdichtendem Beton (SVB) in bewehrten Schalungselementen. Die numerische Simulation des Fließens von Frischbeton kann eine vielversprechende Unterstützung bei der Optimierung von Befüllvorgängen sein, indem diese bereits im Vorfeld vorhergesagt werden. Die Simulation des Fließens von Frischbeton verwendet komplizierte mathematische Modelle und zeitintensive Rechenoperationen. Darüber hinaus wird die Simulationszeit für die Vorhersage des Füllvorgangs zusätzlich deutlich verlängert, weil aufeinanderfolgende Bewehrungsstäbe einzeln zu berücksichtigen sind. Das ist insbesondere für die Simulation von SVB ein entscheidendes Problemfeld, da SVB oft gerade für hochbewehrte Bauteile verwendet wird. Dennoch ist ein weitreichender Einsatz von numerischen Hilfsmitteln bei der Vorhersage von Füllprozessen nur denkbar, wenn die Anwenderfreundlichkeit und eine Zeitersparnis gewährleistet werden können. Um die Simulationszeit zu verkürzen und näher an eine anwenderfreundliche Lösung für die Vorhersage von Füllprozessen zu kommen, wird als Alternative zur einzelnen Modellierung aller Stahlstäbe in dieser Arbeit vorgeschlagen, Zonen mit Bewehrungsstäben als poröse Medien zu modellieren. Infolgedessen wird das Fließen von SVB durch bewehrte Zonen als Strömung eines nicht-Newton’schen Fluides durch ein poröses Medium betrachtet. Durch die Definition charakteristischer Parameter des porösen Mediums kann das veränderte Verhalten des Betons in der porösen Matrix vorhegesagt werden. Dies ermöglicht die Modellierung beliebiger Bewehrungszonen und vereinfacht und beschleunigt folglich die numerische Simulation bewehrter Bauteile. Im Rahmen der Arbeit wird ein Rechenmodell für das Fließverhalten von SVB durch bewehrte Schalungszonen entwickelt. Das Modell verkoppelt das Strömungsverhalten von Beton mit dem makroskopischen Ansatz für den Einfluss von porösen Medien, welche in diesem Fall die Bewehrungsstäbe ersetzen. Das entwickelte Modell wird in eine CFD-Software implementiert und anhand mehrerer numerischer und experimenteller Studien validiert, darunter auch ein maßstabsgetreues Fließexperiment eines hochbewehrten Balkens. Darüber hinaus wird die scheinbare Rheologie des Betons innerhalb der Anordnung der Stahlstäbe untersucht und daraus eine Methode zur Bestimmung unbekannter Parameter für das poröse Medium vorgeschlagen. Es werden hierfür auch normative Tabellen generiert, die die charakteristischen Eigenschaften der porösen Medien für unterschiedliche Bewehrungsanordnungen abbilden. Zuletzt ist der Hauptbeitrag dieser Arbeit das resultierende Numerikpaket, bestehend aus dem numerischen Solver einschließlich des implementierten Modells sowie der Parameterbibliothek. Im Abschluss werden die Verlässlichkeit der Vorhersage von Füllvorgängen durch die Analogie zu porösen Medien erörtert sowie Schlussfolgerungen zur deutlichen Ersparnis an Aufwand und Zeit gegenüber herkömmlichen Methoden vorgenommen
4
Taverna, Joël. « Modélisation mécanique des déformations de la lithosphère ». Grenoble 1, 1998. http://www.theses.fr/1998GRE10084.
Texte intégralRésumé :
Les objectifs de cette these sont de decrire les mecanismes de deformations de la lithosphere en regime compressif, et le controle impose par les parametres mecaniques sur la maniere dont le raccourcissement horizontal est accommode (par la formation de plis, de chevauchements, ou encore par epaississement homogene). Nous avons etudie la nature des instabilites susceptibles de se developper en utilisant des calculs analytiques bases sur la resolution des equations de navier-stokes ainsi que leur evolution pour des taux de deformation importants a partir de modeles analogiques et de calculs numeriques par la methode des elements finis. Les calculs analytiques ont permis de determiner l'influence des differents parametres mecaniques de la lithosphere sur le developpement d'instabilites. En domaine oceanique, le raccourcissement est essentiellement accommode par la formation de plis affectant l'ensemble de la lithosphere. Les parties fragiles de la lithosphere et les contrastes de densite controlent la croissance des instabilites. Deux series d'experiences analogiques ont ensuite permis de confirmer les resultats precedents et d'etudier l'evolution tridimensionnelle d'instabilites lithospheriques apres l'apparition de la fracturation. En domaine continental, le passe tectonique et les heterogeneites mecaniques qui en resultent joue un role essentiel pour l'initiation des plis. Les heterogeneites initiales peuvent favoriser l'apparition de failles aux depends des plis de grandes longueurs d'onde puis la subsidence des portions de lithosphere ainsi delimitees. Les structures ainsi formees s'apparentent a des bassins compressifs. Leur longueur d'onde reste cependant controlee en partie par celle des plis lithospheriques. Ces resultats ont ete completes par des calculs numeriques bases sur la methode des elements finis. Les plis ne se developpent qu'apres plastification complete des parties fragiles de la lithosphere oceanique ou continentale.
5
Finocchio, Debora. « Modellazione numerica agli elementi finiti per sistemi di faglie potenzialmente sismogenetiche nel territorio italiano, con particolare riferimento alla zona della sequenza sismica umbro-marchigiana del 1997 ». Thesis, 2013. http://hdl.handle.net/2122/8530.
Texte intégralRésumé :
Lo scopo fondamentale di questo lavoro è l’applicazione delle tecniche di modellazione numerica per lo studio di sistemi di faglie per verificarne il loro potenziale sismogenetico.
Determinare quale faglia merita più attenzione, dal punto di vista del rischio sismico, è una questione attualmente ancora dibattuta. Lo confermano, ad esempio, i terremoti di l’Aquila nel 2009 e di Sumatra nel 2004. Inoltre, secondo uno studio di Wyss et al. (2012), il numero di morti causati dai recenti terremoti è da 100 a 1000 volte più elevato rispetto ai valori predetti dalla mappa mondiale di hazard.
Le problematiche riguardanti le mappe di hazard dipendono principalmente dal fatto che sono calcolate mediante cataloghi sismici e dati di tipo geologico. Questo comporta un problema dal punto di vista temporale, in quanto i cataloghi sismici registrano eventi che non coprono un intero ciclo sismico, mentre i dati geologici contengono più eventi registrati, ad esempio, dal rigetto superficiale delle faglie.
La questione temporale può essere risolta mediante la modellazione numerica che permette di raccordare i dati a lungo e corto periodo. Infatti, tramite la modellazione numerica, è possibile stimare l’evoluzione di una faglia (in superficie e in profondità) nel periodo intersismico e simulare il caso cosismico. Inoltre la modellazione numerica permette di distinguere le faglie bloccate da quelle sbloccate. Questa distinzione fornisce un elemento utile per valutare la possibilità di un’eventuale rottura. Inoltre è possibile stimare lo stress, la deformazione e la velocità di ricarica di un terremoto.
Ho applicato la modellazione numerica a tre aree rappresentative del territorio italiano. Partendo dal centro Italia, ho studiato la faglia a basso angolo dell’Altotiberina e la sua relazione con le faglie di Colfiorito e della Valle Umbra. Ho approfondito lo studio delle faglie a basso angolo, analizzando il caso della faglia di Messina (Sud Italia). Infine, ho studiato l’area esterna del sud Alpino (nord Italia), caratterizzata da un sistema compressivo, che comprende il thrust del Montello ed il thrust di Bassano. Ho modellato numericamente ognuna di queste faglie o sistemi di faglie utilizzando diverse condizioni al contorno e parametri reologici in accordo con l’area di studio. I risultati sono stati confrontati con dati di tipo geodetico, geologico e geofisico.
E’ stato possibile verificare che, la modellazione numerica fornisce un ottimo sostegno per la modellazione analogica, contribuendo a dare maggiore completezza al risultato e a simulare alcune proprietà dei materiali con grande precisione.
Il risultato di un modello numerico varia principalmente al variare delle condizioni al contorno imposte, quindi dalla geometria, dai parametri reologici, e dal tipo di meccanismo utilizzato per riprodurre la deformazione di un’area.
I risultati ottenuti in questo lavoro mostrano che la faglia Altotiberina è completamente bloccata al contrario della faglia di Colfiorito e la faglia della Valle Umbra che si muovono in parte come delle faglie sbloccate. Il campo deformativo dell’area sembra essere guidato da una trazione posta alla base della litosfera.
Per quanto riguarda il sistema di thrust del Montello, ho potuto verificare che la porzione bloccata del thrust di Bassano ha un grande potenziale sismogenetico rispetto al thrust del Montello e al thrust antitetico al Montello, che risultano sbloccate.
Assumendo che l’ampiezza delle faglie bloccate sia proporzionale all’ampiezza del terremoto, è stato possibile stimare la magnitudo massima attesa per ogni porzione di faglia bloccata, calcolata mediante la modellazione numerica. In particolare, la faglia di Bassano e la faglia Altotiberina sembrano avere un forte potenziale sismogenetico, in quanto potrebbe avere una magnitudo massima attesa di circa 7.Università degli studi di Urbino
Unpublished
open
6
Scandura, Danila. « Physical-Mathematical modeling and numerical simulations of stress-strain state in seismic and volcanic regions ». Thesis, 2009. http://hdl.handle.net/2122/5952.
Texte intégralRésumé :
The strain-stress state generated by faulting or cracking and influenced by the strong heterogeneity of the internal earth structure precedes and accompanies volcanic and seismic activity. Particularly, volcanic eruptions are the culmination of long and complex geophysical processes and physical processes which involve the generation of magmas in the mantle or in the lower crust, its ascent to shallower levels, its storage and differentiation in shallow crustal chambers, and, finally, its eruption at the Earth’s surface. Instead, earthquakes are a frictional stick-slip instability arising along pre-existing faults within the brittle crust of the Earth. Long-term tectonic plate motion causes stress to accumulate around faults until the frictional strength of the fault is exceeded.
The study of these processes has been traditionally carried out through different geological disciplines, such as petrology, structural geology, geochemistry or sedimentology. Nevertheless, during the last two decades, the development of physical of earth as well as the introduction of new powerful numerical techniques has progressively converted geophysics into a multidisciplinary science. Nowadays, scientists with very different background and expertises such as geologist, physicists, chemists, mathematicians and engineers work on geophysics. As any multidisciplinary field, it has been largely benefited from these collaborations. The different ways and procedures to face the study of volcanic and seismic phenomena do not exclude each other and should be regarded as complementary.
Nowadays, numerical modeling in volcanology covers different pre-eruptive, eruptive and post-eruptive aspects of the general volcanic phenomena. Among these aspects, the pre-eruptive process, linked to the continuous monitoring, is of special interest because it contributes to evaluate the volcanic risk and it is crucial for hazard assessment, eruption prediction and risk mitigation at volcanic unrest.
large faults. The knowledge of the actual activity state of these sites is not only an academic topic but it has crucial importance in terms of public security and eruption and earthquake forecast.
However, numerical simulation of volcanic and seismic processes have been traditionally developed introducing several simplifications: homogeneous half-space, flat topography and elastic rheology. These simplified assumptions disregards effects caused by topography, presence of medium heterogeneity and anelastic rheology, while they could play an important role in Moreover, frictional sliding of a earthquake generates seismic waves that travel through the earth, causing major damage in places nearby to the modeling procedure
This thesis presents mathematical modeling and numerical simulations of volcanic and seismic processes. The subject of major interest has been concerned on the developing of mathematical formulations to describe seismic and volcanic process. The interpretation of geophysical parameters requires numerical models and algorithms to define the optimal source parameters which justify observed variations. In this work we use the finite element method that allows the definition of real topography into the computational domain, medium heterogeneity inferred from seismic tomography study and the use of complex rheologies. Numerical forward method have been applied to obtain solutions of ground deformation expected during volcanic unrest and post-seismic phases, and an automated procedure for geodetic data inversion was proposed for evaluating slip distribution along surface rupture.Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania
Unpublished
3.6. Fisica del vulcanismo
open
7
Vasilic, Ksenija. « A Numerical Model for Self-Compacting Concrete Flow through Reinforced Sections : a Porous Medium Analogy ». Doctoral thesis, 2014. https://tud.qucosa.de/id/qucosa%3A29183.
Texte intégralRésumé :
This thesis addresses numerical simulations of self-compacting concrete (SCC) castings and suggests a novel modelling approach that treats reinforcement zones in a formwork as porous media.
As a relatively new field in concrete technology, numerical simulations of fresh concrete flow can be a promising aid to optimise casting processes and to avoid on-site casting incidents by predicting the flow behaviour of concrete during the casting process. The simulations of fresh concrete flow generally involve complex mathematical modelling and time-consuming computations. In case of a casting prediction, the simulation time is additionally significantly increased because each reinforcement bar occurring in succession has to be considered one by one. This is particularly problematic when simulating SCC casting, since this type of concrete is typically used for heavily reinforced structural members. However, the wide use of numerical tools for casting prediction in practice is possible only if the tools are user-friendly and simulations are time-saving.
In order to shorten simulation time and to come closer to a practical tool for casting prediction, instead to model steel bars one by one, this thesis suggests to model zones with arrays of steel bars as porous media. Consequently, one models the flow of SCC through a reinforcement zone as a free-surface flow of a non-Newtonian fluid, propagating through the medium. By defining characteristic parameters of the porous medium, the influence on the flow and the changed (apparent) behaviour of concrete in the porous matrix can be predicted. This enables modelling of any reinforcement network as a porous zone and thus significantly simplifies and fastens simulations of reinforced components’ castings.
Within the thesis, a computational model for SCC flow through reinforced sections was developed. This model couples a fluid dynamics model for fresh concrete and the macroscopic approach for the influence of the porous medium (formed by the rebars) on the flow. The model is implemented into a Computational Fluid Dynamics software and validated on numerical and experimental studies, among which is a large-scale laboratory casting of a highly reinforced beam. The apparent rheology of concrete within the arrays of steel bars is studied and a methodology to determine unknown input parameters for the porous medium is suggested. Normative tables defining characteristic porous medium parameters as a function of the topology of the rebar zone for different reinforcement cases are generated. Finally, the major contribution of this work is the resulting numerical package, consisting of the numerical solver and the parameter library. The thesis concludes on the ability of the porous medium analogy technique to reliably predict the concrete casting behaviour, while being significantly easier to use and far less time consuming than existing tools.Die Arbeit behandelt die numerische Modellierung des Fließverhaltens von selbst-verdichtendem Beton (SVB) in bewehrten Schalungselementen. Die numerische Simulation des Fließens von Frischbeton kann eine vielversprechende Unterstützung bei der Optimierung von Befüllvorgängen sein, indem diese bereits im Vorfeld vorhergesagt werden. Die Simulation des Fließens von Frischbeton verwendet komplizierte mathematische Modelle und zeitintensive Rechenoperationen. Darüber hinaus wird die Simulationszeit für die Vorhersage des Füllvorgangs zusätzlich deutlich verlängert, weil aufeinanderfolgende Bewehrungsstäbe einzeln zu berücksichtigen sind. Das ist insbesondere für die Simulation von SVB ein entscheidendes Problemfeld, da SVB oft gerade für hochbewehrte Bauteile verwendet wird. Dennoch ist ein weitreichender Einsatz von numerischen Hilfsmitteln bei der Vorhersage von Füllprozessen nur denkbar, wenn die Anwenderfreundlichkeit und eine Zeitersparnis gewährleistet werden können. Um die Simulationszeit zu verkürzen und näher an eine anwenderfreundliche Lösung für die Vorhersage von Füllprozessen zu kommen, wird als Alternative zur einzelnen Modellierung aller Stahlstäbe in dieser Arbeit vorgeschlagen, Zonen mit Bewehrungsstäben als poröse Medien zu modellieren. Infolgedessen wird das Fließen von SVB durch bewehrte Zonen als Strömung eines nicht-Newton’schen Fluides durch ein poröses Medium betrachtet. Durch die Definition charakteristischer Parameter des porösen Mediums kann das veränderte Verhalten des Betons in der porösen Matrix vorhegesagt werden. Dies ermöglicht die Modellierung beliebiger Bewehrungszonen und vereinfacht und beschleunigt folglich die numerische Simulation bewehrter Bauteile. Im Rahmen der Arbeit wird ein Rechenmodell für das Fließverhalten von SVB durch bewehrte Schalungszonen entwickelt. Das Modell verkoppelt das Strömungsverhalten von Beton mit dem makroskopischen Ansatz für den Einfluss von porösen Medien, welche in diesem Fall die Bewehrungsstäbe ersetzen. Das entwickelte Modell wird in eine CFD-Software implementiert und anhand mehrerer numerischer und experimenteller Studien validiert, darunter auch ein maßstabsgetreues Fließexperiment eines hochbewehrten Balkens. Darüber hinaus wird die scheinbare Rheologie des Betons innerhalb der Anordnung der Stahlstäbe untersucht und daraus eine Methode zur Bestimmung unbekannter Parameter für das poröse Medium vorgeschlagen. Es werden hierfür auch normative Tabellen generiert, die die charakteristischen Eigenschaften der porösen Medien für unterschiedliche Bewehrungsanordnungen abbilden. Zuletzt ist der Hauptbeitrag dieser Arbeit das resultierende Numerikpaket, bestehend aus dem numerischen Solver einschließlich des implementierten Modells sowie der Parameterbibliothek. Im Abschluss werden die Verlässlichkeit der Vorhersage von Füllvorgängen durch die Analogie zu porösen Medien erörtert sowie Schlussfolgerungen zur deutlichen Ersparnis an Aufwand und Zeit gegenüber herkömmlichen Methoden vorgenommen.
Chapitres de livres sur le sujet "Numerical model, faults, rheology"
1
Giraud, L. « A Lattice Boltzmann Model for the Numerical Simulation of Non-Linear Viscoelastic Fluids ». Dans Progress and Trends in Rheology V, 349–50. Heidelberg : Steinkopff, 1998. http://dx.doi.org/10.1007/978-3-642-51062-5_166.
Texte intégral
2
Mitsoulis, E., et X. L. Luo. « Convergence Studies in the Numerical Simulation of Viscoelastic Melts Using the K-Bkz Model ». Dans Third European Rheology Conference and Golden Jubilee Meeting of the British Society of Rheology, 361–64. Dordrecht : Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0781-2_125.
Texte intégral
3
Finzi, Yaron, Elizabeth H. Hearn, Yehuda Ben-Zion et Vladimir Lyakhovsky. « Structural Properties and Deformation Patterns of Evolving Strike-slip Faults : Numerical Simulations Incorporating Damage Rheology ». Dans Mechanics, Structure and Evolution of Fault Zones, 1537–73. Basel : Birkhäuser Basel, 2009. http://dx.doi.org/10.1007/978-3-0346-0138-2_2.
Texte intégral
4
BARANGER, J., et D. SANDRI. « NUMERICAL ANALYSIS OF SOME FINITE ELEMENT METHOD FOR THE APPROXIMATION OF DIFFERENTIAL MODEL FOR VISCOELASTIC FLOW ». Dans Theoretical and Applied Rheology, 253–55. Elsevier, 1992. http://dx.doi.org/10.1016/b978-0-444-89007-8.50099-x.
Texte intégral
5
« Model test and numerical simulation of tunnel in country rocks with faults ». Dans Boundaries of Rock Mechanics, 775–78. CRC Press, 2008. http://dx.doi.org/10.1201/9780203883204-149.
Texte intégral
6
Zhang, N., B. Yang, S. Wang et W. Liu. « Model test and numerical simulation of tunnel in country rocks with faults ». Dans Boundaries of Rock Mechanics, 755–58. Taylor & Francis, 2008. http://dx.doi.org/10.1201/9780203883204.ch141.
Texte intégral
7
Li, Linfeng, Yating Yu, Qin Hong et Zhenwei Wang. « Numerical Investigation on Faults Diagnosis for AC Induction Machine by Magnetic Flux Distribution ». Dans Studies in Applied Electromagnetics and Mechanics. IOS Press, 2020. http://dx.doi.org/10.3233/saem200016.
Texte intégralRésumé :
AC induction machines are widely used in electric servo drive, information processing, transportation and other fields. However, the unexpected faults cause the serious threat for the normal operation and operator’s safety. Therefore, timely faults diagnosis is an effective way to ensure the AC induction machines to work in health condition. In AC induction machines, magnetic field is the basis of energy conversion of motor, and the faults have the directly influence on the electromagnetic field distribution. In this paper, 2D numerical model of the AC squirrel-cage asynchronous induction machine is built by using COMSOL Multiphysics according to finite element method; Then, the magnetic flux distribution of AC induction motor with three different faults which commonly occurs in engineering are simulated. Base on the numerical simulation, the influence of the different faults on the magnetic distribution is discussed in detail. The investigation is beneficial to find a nondestructive fault diagnosis approach to the induction machine.
8
« Inter-well tracer test models for underground formations having conductive faults : development of a numerical model and comparison against analytical models ». Dans Mathematical and Numerical Modeling in Porous Media, 127–42. CRC Press, 2012. http://dx.doi.org/10.1201/b12080-14.
Texte intégral
9
Albattat, Rami, et Hussein Hoteit. « Modeling Lost-Circulation into Fractured Formation in Rock Drilling Operations ». Dans Drilling Technology. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95805.
Texte intégralRésumé :
Loss of circulation while drilling is a challenging problem that may interrupt drilling operations, reduce efficiency, and increases cost. When a drilled borehole intercepts conductive faults or fractures, lost circulation manifests as a partial or total escape of drilling, workover, or cementing fluids into the surrounding rock formations. Studying drilling fluid loss into a fractured system has been investigated using laboratory experiments, analytical modeling, and numerical simulations. Analytical modeling of fluid flow is a tool that can be quickly deployed to assess lost circulation and perform diagnostics, including leakage rate decline and fracture conductivity. In this chapter, various analytical methods developed to model the flow of non-Newtonian drilling fluid in a fractured medium are discussed. The solution methods are applicable for yield-power-law, including shear-thinning, shear-thickening, and Bingham plastic fluids. Numerical solutions of the Cauchy equation are used to verify the analytical solutions. Type-curves are also described using dimensionless groups. The solution methods are used to estimate the range of fracture conductivity and time-dependent fluid loss rate, and the ultimate total volume of lost fluid. The applicability of the proposed models is demonstrated for several field cases encountering lost circulations.
10
Hamidi, Hodjatollah. « A General Framework of Algorithm-Based Fault Tolerance Technique for Computing Systems ». Dans Analyzing Security, Trust, and Crime in the Digital World, 1–21. IGI Global, 2014. http://dx.doi.org/10.4018/978-1-4666-4856-2.ch001.
Texte intégralRésumé :
The Algorithm-Based Fault Tolerance (ABFT) approach transforms a system that does not tolerate a specific type of faults, called the fault-intolerant system, to a system that provides a specific level of fault tolerance, namely recovery. The ABFT philosophy leads directly to a model from which error correction can be developed. By employing an ABFT scheme with effective convolutional code, the design allows high throughput as well as high fault coverage. The ABFT techniques that detect errors rely on the comparison of parity values computed in two ways. The parallel processing of input parity values produce output parity values comparable with parity values regenerated from the original processed outputs and can apply convolutional codes for the redundancy. This method is a new approach to concurrent error correction in fault-tolerant computing systems. This chapter proposes a novel computing paradigm to provide fault tolerance for numerical algorithms. The authors also present, implement, and evaluate early detection in ABFT.
Actes de conférences sur le sujet "Numerical model, faults, rheology"
1
Mitran, Sorin M., Albert Co, Gary L. Leal, Ralph H. Colby et A. Jeffrey Giacomin. « A Numerical Model of Viscoelastic Layer Entrainment by Airflow in Cough ». Dans THE XV INTERNATIONAL CONGRESS ON RHEOLOGY : The Society of Rheology 80th Annual Meeting. AIP, 2008. http://dx.doi.org/10.1063/1.2964779.
Texte intégral
2
Ohta, Mitsuhiro, Kei Onodera, Yutaka Yoshida, Mark Sussman, Albert Co, Gary L. Leal, Ralph H. Colby et A. Jeffrey Giacomin. « Three-Dimensional Numerical Simulations of a Rising Bubble in a Viscoelastic FENE-CR Model Fluid ». Dans THE XV INTERNATIONAL CONGRESS ON RHEOLOGY : The Society of Rheology 80th Annual Meeting. AIP, 2008. http://dx.doi.org/10.1063/1.2964886.
Texte intégral
3
Vinay, Guillaume, Anthony Wachs, Albert Co, Gary L. Leal, Ralph H. Colby et A. Jeffrey Giacomin. « A 1.5D Numerical Model for Weakly Compressible Viscoplastic and Thixotropic Flows : Application to the Start-up of Waxy Crude Oils in Pipeline ». Dans THE XV INTERNATIONAL CONGRESS ON RHEOLOGY : The Society of Rheology 80th Annual Meeting. AIP, 2008. http://dx.doi.org/10.1063/1.2964657.
Texte intégral
4
Reasor, Daniel A., Jonathan R. Clausen et Cyrus K. Aidun. « Direct Numerical Simulation of Cellular Blood Flow Through a Model Arteriole Bifurcation ». Dans ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19061.
Texte intégralRésumé :
Blood is composed of a suspension of red blood cells (RBCs) suspended in plasma, and the presence of the RBCs substantially changes the flow characteristics and rheology of these suspensions. The viscosity of blood varies with the hematocrit (volume fraction of RBCs), which is a result not seen in Newtonian fluids. Additionally, RBCs are deformable, which can alter suspension dynamics. Understanding the physics in these flows requires accurately simulating the suspended phase to recover the microscale, and a subsequent analysis of the rheology to ascertain the continuum-level effects caused by the changes at the particle level. The direct numerical simulation of blood flow including RBC migration effects has the capability to resolve the Fåhraeus effect of observing low hematocrit values near walls, the subsequent cell-depleted layer, and the presence of velocity profile blunting due to the distribution of RBCs.
5
Bai, Zhuofu, Gang Shu et Andy Podgurski. « NUMFL : Localizing Faults in Numerical Software Using a Value-Based Causal Model ». Dans 2015 IEEE 8th International Conference on Software Testing, Verification and Validation (ICST). IEEE, 2015. http://dx.doi.org/10.1109/icst.2015.7102597.
Texte intégral
6
Massai, Diana, Raffaele Ponzini, Diego Gallo, Luca Antiga, Giuseppe Passoni, Franco Maria Montevecchi, Alberto Redaelli et Umberto Morbiducci. « Effects of Blood Rheology on Flow Topology and Blood-Vessel Interaction in Image-Based Carotid Bifurcation Numerical Model ». Dans ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206154.
Texte intégralRésumé :
In recent years, interest is growing on compact measures for assessing the role of local hemodynamics in the pathogenesis of atherosclerosis and atherogenesis. CFD and its power in evaluating and predicting the effect of some hemodynamic variables in vascular disease is becoming a key factor in clinical research. Recently, Lee and Steinman [1] assessed the importance of blood rheology assumptions to ascertain the effect of constitutive relation for blood on local wall shear stress (WSS) and on the correlated vascular pathology. We present a preliminary in silico investigation on the sensitivity of helical flow measure with respect to the blood constitutive adopted model. Our main objective was to verify if, through the carotid bifurcation model, the rheological properties of blood significantly influence the bulk flow topology, whose evolution and stability are strictly linked to helicity. In fact helicity — an invariant in fluid dynamics — has been demonstrated to describe and reveal the global organization in a fluid flow. For this purpose several blood models (Newtonian and non-Newtonian) were implemented. A specific Lagrangian-based “bulk” flow descriptor, the Helical Flow Index (HFI) [2], was calculated in order to get a “measure” of the helical structure in the blood flow. Therefore, its sensitivity to blood rheology and hematocrit (Ht) was assessed and compared with the sensitivity of WSS based on other fluid dynamics descriptors (Time Averaged WSS, TAWSS, and Oscillating Shear Index, OSI).
7
Occari, Matteo, Valentina Mazzanti, Francesco Mollica, Enrico Munari, Michele Pinelli et Alessio Suman. « Numerical Simulations of a Centrifugal Pump With a Non-Newtonian Fluid : Influence on Performances of Different Rheological Modelling ». Dans ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-4940.
Texte intégralRésumé :
Abstract Centrifugal pumps change their performance with respect to water when processing non-Newtonian fluids. Many aspects about pumping of non-Newtonian fluids remain to be clarified due to complexity of the matter and the scarcity of investigations. In addition to experimental tests, in recent years some CFD fluid dynamics simulations have been realized to analyze the performance of centrifugal pumps with non-Newtonian fluids. Knowledge of rheology is required to correctly simulate the fluid inside the pump and predict the performance. The aim of this work is to emphasize the criticalities in the simulation of centrifugal pumps with non-Newtonian fluids, since, starting from the same rheological data, can be deduced different rheological laws, however reliable, that produce different effects on the simulations. In this paper, the performances of a model pump were measured experimentally with pear juice and accompanied by the rheological characterization of the fluid. Subsequently, the pump was simulated using five different rheology laws, all fitted to the same experimental rheogram, that differ from each other in predicting viscosity out of shear rate range experimentally measured. The pump performances were affected by the different rheology implemented. The simulations showed that the shear rates developed inside the pump are much higher than those measured with the rheometer. Consequently is necessary to achieve higher shear rates in the experimental rheogram to make sure to correctly model the rheology for shear rates values typically present in the pump.
8
Yu, Yinquan, Chao Bi, Quan Jiang, Song Lin, Phyu Nu Hla, Nay Lin Htun Aung et A. A. Mamun. « Analytical and Numerical Study Rotor Faults in PM Synchronous Motor ». Dans ASME 2013 Conference on Information Storage and Processing Systems. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/isps2013-2857.
Texte intégralRésumé :
In order to achieve high area density of HDD to 10Tbit/in2, both radial and axial direction Repeatable Run-Out (RRO) and None repeatable Run-Out (NRRO) of spindle motor in HDD should be significantly reduced. That means the high performance spindle motor is need. Currently, the spindle motor used in HDD uses a rotating shaft FDB which structure likes slender cantilever beam to support the rotor and the problem of this kind of structure is reported in [1]. This structure cannot meet HDD high TPI requirements and should be replaced by the fixed shaft FDB spindle motor and the analytical model is shown in Fig. 1. Moreover, different types of Unbalance Magnetic Pull (UMP) of the Spindle motor and induced vibration should be fully studied. In order to fully understand motor vibration behavior, a thorough theoretical derivation of motor dynamics should be carried out as they can disclose clearly the global performance of the motor. Generally, four types of UMP reported in [1]–[3] can generate the motor lateral and axis vibration and produce motor acoustic noise. Researchers have studied vibration and acoustic signals in recent years[1]–[6]. In this paper, the PMSM mathematic model has introduced and validated by 12 slots and 5 pole-pairs PM surface mounting Synchronous motor M1 simulation case study. This type of Permanent Magnetic Synchronous motor (PMSM) is using in many applications, e.g.
9
Renouf, Mathieu. « Physico-Chemical Modeling of Third Body Rheology ». Dans STLE/ASME 2010 International Joint Tribology Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ijtc2010-41036.
Texte intégralRésumé :
The well-known concept of third body was introduced by Godet in the seventies to characterise the discontinuous and heterogeneous interface that separates two bodies in contact. This thin layer (from some nanometers to some micrometers high) appears to possess its own rheology depending of contact conditions, material properties and often, extra unknown parameters. If its main common role concerns essentially mechanical aspects such as velocity accommodation, load carrying capacity and solid lubricant, it plays an important role in other physical aspects. For example, it ensures the thermal continuity between two bodies in contact and explains the jump of temperature observed experimentally. Moreover, it is able to capture the maximal temperature through its thickness. Due to the difficulty to instrument a real contact without disturbing the local rheology, observations of the third body rheology occur only on simplified experimental set-up. To reproduce and try to understand “real contact in presence of third body”, numerical tools have been developed and adapt to face new challenge raised by the third-body concept. The discontinuity and heterogeneity of such interface led researchers to use discrete element methods (DEM) to describe its evolution. Several improvments of the method allow to deal with the mechanical and the thermal behaviour of such media but without interactions. The integration of physicochemical aspects is presented in the paper to link thermal and mechanical behaviour and proposed a model able to represent the multi-physical feature of a contact interface.
10
Silva, Thiago Geraldo, Luis Kin Miyatake, Rafael Madeira Barbosa, Andre Goncalves Medeiros, Otavio Ciribelli Borges, Marcia Cristina Oliveira et Felipe Mauro Cardoso. « AI Based Water-in-Oil Emulsions Rheology Model for Value Creation in Deepwater Fields Production Management ». Dans Offshore Technology Conference. OTC, 2021. http://dx.doi.org/10.4043/31173-ms.
Texte intégralRésumé :
Abstract This work aims to present a new paradigm in the Exploration & Production (E&P) segment using Artificial Intelligence for rheological mapping of produced fluids and forecasting their properties throughout the production life cycle. The expected gain is to accelerate the process of prioritizing target fields for application of flow improvers and, as a consequence, to generate anticipation of revenue and value creation. Rheological data from laboratory analyses of water-in-oil emulsions from different production fields collected over the years are used in a machine learning framework, which enables a modeling based on supervised learning. The Artificial Intelligence infers the emulsion viscosity as a function of input parameters, such as API gravity, water cut and dehydrated oil viscosity. The modeling of emulsified fluids uses correlations that, in general, do not represent the viscosity emulsion suitably. Currently, an improvement over empirical correlations can be achieved via rheological characterization using tests from onshore laboratories, which have been generating a database for different Petrobras reservoirs over the years. The dataset used in the artificial intelligence framework results in a machine learning model with generalization ability, showing a good match between experimental and calculated data in both training and test datasets. This model is tested with a great deal of oils from different reservoirs, in an extensive range of API gravity, presenting a suitable mean absolute percentage error. In addition to that, the result preserves the expected physical behavior for the emulsion viscosity curve. Consequently, this approach eliminates frequent sampling requirements, which means lower logistical costs and faster actions in the decision making process with respect to flow improvers injection. Moreover, by embedding the AI model into a numerical flow simulation software, the overall flow model can estimate more reliably production curves due to better representation of the rheological fluid characteristics.