Blar i NTNU Open på forfatter "Hansen, Alex"
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Motion Prediction by Optimal Paths Through Disordered Landscapes
Fromreide, Mads (Master thesis, 2014)The ability to navigate safely and efficiently through a given landscape is relevant for any intelligent moving object. Examples range from robotic science and traffic analysis to the behavior within an ecosystem. Through ... -
Network topology of the desert rose
Hope, Sigmund Mongstad; Kundu, Sumanta; Roy, Chandreyee; Manna, S. S.; Hansen, Alex (Journal article; Peer reviewed, 2015-09-08)Desert roses are gypsum crystals that consist of intersecting disks. We determine their geometrical structure using computer assisted tomography. By mapping the geometrical structure onto a graph, the topology of the desert ... -
Non-equilibrium Statistical Mechanics of Two-Phase Flow in Porous Media
Savani, Isha (Doctoral theses at NTNU;2016:335, Doctoral thesis, 2016)The world that we live in is a consortium of fluid-solid interactions. The field of two-phase flow in porous materials poses interesting questions regarding such interactions. In this project, we develop a statistical ... -
Non-isothermal transport of multi-phase fluids in porous media. Constitutive equations
Kjelstrup, Signe; Bedeaux, Dick; Hansen, Alex; Hafskjold, Bjørn; Galteland, Olav (Journal article; Peer reviewed, 2019)We define a representative elementary volume of a porous medium in terms of lumped extensive variables, including properties of homogeneous phases, interfaces, and contact lines. Using the grand potential, we define the ... -
Non-isothermal transport of multi-phase fluids in porous media; The entropy production
Kjelstrup, Signe; Bedeaux, Dick; Hansen, Alex; Hafskjold, Bjørn; Galteland, Olav (Journal article; Peer reviewed, 2018)We derive the entropy production for transport of multi-phase fluids in a non-deformable, porous medium exposed to differences in pressure, temperature, and chemical potentials. Thermodynamic extensive variables on the ... -
Numerical methods for solving complex heat exchanger models in transient operation
Skåre, Bjørnar Gundersen (Master thesis, 2014)Heat exchangers are important in many industrial systems. In order to maximizeheat transfer while fulfilling requirements to size and weight, it is crucial to havegood numerical tools available. Sintef has developed a ... -
On the Simulation of Electromagnetic Wave Scattering by Periodic and Randomly Rough Layered Structures based on the Reduced Rayleigh Equations: Theory, numerical analysis and applications
Banon, Jean-Philippe (Doctoral theses;2018:306, Doctoral thesis, 2018)A great number of natural phenomena that we observe, as well as numerous man-made objects we use in our everyday life, are made possible thanks to the interaction between light and matter. In particular, when light is ... -
On the Stability of the Local Load Sharing Fiber Bundle Model
Bering, Eivind (Master thesis, 2016)This thesis investigates a generalized history-independent local load sharing (LLS) fiber bundle model for two dimensional interfacial fractures. When the failure threshold of the fibers are assigned according to the ... -
Onsager-symmetry obeyed in athermal mesoscopic systems: Two-phase flow in porous media
Winkler, Mathias; Gjennestad, Magnus Aashammer; Bedeaux, Dick; Kjelstrup, Signe; Cabriolu, Raffaela; Hansen, Alex (Peer reviewed; Journal article, 2020)We compute the fluid flow time correlation functions of incompressible, immiscible two-phase flow in porous media using a 2D network model. Given a properly chosen representative elementary volume, the flow rate distributions ... -
Optimal path for the flow of yield stress fluids
Lanza, Federico (Doctoral theses at NTNU;2023:386, Doctoral thesis, 2023)Numerous real-world applications depend on understanding how liquids or gases flow through the tiny holes of materials like soil or rocks, called “porous media”. These applications range from cleaning up polluted groundwater ... -
Optimal Paths in Random Conductor Networks
Stornes, Morten (Master thesis, 2013)In this master thesis, the spanning path through a random conductor network with aquenched threshold distribuion has been studied. An argument is made using a hierar-chial model, that for bonds having a piecewise linear ... -
Parallel Instabilities in Two-Phase Flow in Porous Media
Vassvik, Morten (Master thesis, 2014)Two immiscible fluids flowing in parallel with respect to the interface separating them in a two-dimensional porous medium has been studied using a dynamic network model. Two immiscible fluids, one wetting and the other ... -
Parameterizations of immiscible two-phase flow in porous media
Pedersen, Håkon; Hansen, Alex (Peer reviewed; Journal article, 2023)A fundamental variable characterizing immiscible two-phase flow in porous media is the wetting saturation, which is the ratio between the pore volume filled with wetting fluid and the total pore volume. More generally, ... -
Phase transitions and correlations in fracture processes where disorder and stress compete
Sinha, Santanu; Roy, Subhadeep; Hansen, Alex (Peer reviewed; Journal article, 2020)We study the effect of the competition between disorder and stress enhancement in fracture processes using the local load sharing fiber bundle model, a model that hovers on the border between analytical tractability and ... -
Predicting Motion Patterns Using Optimal Paths
Fromreide, Mads; Hansen, Alex (Journal article; Peer reviewed, 2021) -
Pressure Fluctuations and Correlations in Steady State two Phase Flow in Porous Media
Helland, Sjur Peder (Master thesis, 2013)This thesis investigates the burst size distribution and pressurecorrelation profiles of steady state two phase flow in porous mediaat various capillary numbers and viscosity ratios. A network modelis used to simulate ... -
Pressure Fluctuations in Steady State Two-Phase Flow in Porous Media
Lisø, Daniel (Master thesis, 2013)Several aspects of two-phase flow in porous are examined numerically.The burst size distributions in both the invasion phase and steady stateare computed; above a threshold, the steady state distribution is found tobe ... -
Properties of fracture networks and other network systems
Andresen, Christian André (Doctoral Theses at NTNU, 1503-8181; 2009:5, Doctoral thesis, 2009) -
Rheology of high-capillary number two-phase flow in porous media
Sinha, Santanu; Gjennestad, Magnus Aashammer; Vassvik, Morten; Winkler, Mathias; Hansen, Alex; Flekkøy, Eirik Grude (Journal article; Peer reviewed, 2019)Flow of immiscible fluids in porous media at high capillary numbers may be characterized by an effective viscosity. We demonstrate that the effective viscosity is well-described by the Lichtenecker-Rother equation. Depending ... -
Role of Pore-Size Distribution on Effective Rheology of Two-Phase Flow in Porous Media
Roy, Subhadeep; Sinha, Santanu; Hansen, Alex (Peer reviewed; Journal article, 2021)Immiscible two-phase flow of Newtonian fluids in porous media exhibits a power law relationship between flow rate and pressure drop when the pressure drop is such that the viscous forces compete with the capillary forces. ...