Search results for "Physics::Geophysics"
showing 10 items of 261 documents
Self-consistent subduction initiation induced by mantle flow
2015
Mantle circulation in planets with strongly temperature-dependent viscosity results in stagnant-lid convection. It is fundamental to understand how this stagnant-lid regime can change into a plate-like convection regime as on the present-day Earth. Here, we use 2D numerical models to study subduction initiation from an initial stagnant lid with laboratory-consistent parameters and without pre-existing weak zones or kinematic boundary conditions. Our results show that subduction can be initiated dynamically as a result of a thermal localization instability. The lithosphere may deform in a stagnant-lid mode, an un-necking mode, a symmetric-subduction mode or an asymmetric-subduction mode. The…
Coupled Multi-Field Continuum Methods for Porous Media Fracture
2015
The focus of the present contribution is on the numerical modelling of hydraulic fracture in fluid-saturated heterogeneous materials, which can be carried out on a macroscopic scale using extended continuum porous media theories. This accounts for the crack nucleation and propagation, deformation of the solid matrix and change in the flow of the interstitial fluid. In particular, fluid-saturated porous materials basically represent volumetrically interacting solid-fluid aggregates, which are modelled using the Theory of Porous Media. The hydraulic- or tension-induced fracture occurs in the solid matrix and is simulated using a diffusive phase-field modelling approach. This way of fracture t…
Equivalent continuum-based upscaling of flow in discrete fracture networks: The fracture-and-pipe model
2021
Abstract. Predicting effective permeabilities of fractured rock masses is a key component of reservoir modelling. This is often realized with the discrete fracture network (DFN) method, where single-phase incompressible fluid flow is modelled in discrete representations of individual fractures in a network. Depending on the overall number of fractures, this can result in significant computational costs. Equivalent continuum models (ECM) provide an alternative approach by subdividing the fracture network into a grid of continuous medium cells, over which hydraulic properties are averaged for fluid flow simulations. While this has the advantage of lower computational costs and the possibility…
Permeability and effective porosity of porous media
1997
The concept of permeability of porous media is discussed, and a modification of Kozeny’s permeability equation to include the effect of effective porosity is introduced. An analytical expression for the specific surface area of a system constructed of randomly placed identical obstacles with unrestricted overlap is derived, and a lattice-gas cellular automaton method is then used to simulate the dependence on porosity of permeability, tortuosity, and effective porosity for a flow of Newtonian uncompressible fluid in this two-dimensional porous substance. The simulated permeabilities can well be explained by the concept of effective porosity, and the exact form of the specific surface area. …
Field and numerical study of river confluence flow structures
2010
River hydrodynamics Turbulent open channel flow and transport phenomena
X-ray computed tomography and numerical analysis of water-saturated porous materials
2012
A method for imaging a water-saturated porous material is developed in order to simulate a fluid flow through it using the Lattice Boltzmann method. The value of its flow permeability is compared to the value for the same sample when it is dry. An explanation for the difference in the experimental values of permeability for air and water is sought. A reference is given by experimental values from flow measurements that are interpreted according to Darcy's law of permeability.
"Table 4" of "Multiplicity dependence of K*(892)$^{0}$ and $\phi$(1020) production in pp collisions at $\sqrt{s}$ = 13 TeV"
2020
K$^{*0}$ transverse momentum spectrum - V0M multiplicity class IV+V, average of particle and antiparticle
Before and after: how has the SNO neutral current measurement changed things?
2002
We present Before and After global oscillation solutions, as well as predicted Before and After values and ranges for ten future solar neutrino observables (for BOREXINO, KamLAND, SNO, and a generic p-p neutrino detector). The 'Before' case includes all solar neutrino data (and some theoretical improvements) available prior to April 20, 2002 and the After case includes, in addition, the new SNO data on the CC, NC, and day-night asymmetry. We have performed global analyses using the full SNO day-night energy spectrum and, alternatively, using just the SNO NC and CC rates and the day-night asymmetry. The LMA solution is the only currently allowed MSW oscillation solution at similar to99% CL. …
Supernova neutrino burst detection with the Deep Underground Neutrino Experiment
2021
The Deep Underground Neutrino Experiment (DUNE), a 40-kton underground liquid argon time projection chamber experiment, will be sensitive to the electron-neutrino flavor component of the burst of neutrinos expected from the next Galactic core-collapse supernova. Such an observation will bring unique insight into the astrophysics of core collapse as well as into the properties of neutrinos. The general capabilities of DUNE for neutrino detection in the relevant few- to few-tens-of-MeV neutrino energy range will be described. As an example, DUNE’s ability to constrain the νe spectral parameters of the neutrino burst will be considered. peerReviewed
Appendix C. Posterior distributions of the CR-SEM parameters (conditional on the covariates being in the model).
2016
Posterior distributions of the CR-SEM parameters (conditional on the covariates being in the model).