A parametric acceleration of multilevel Monte Carlo convergence for nonlinear variably saturated flow

We present a multilevel Monte Carlo (MLMC) method for the uncertainty quantification of variably saturated porous media flow that is modeled using the Richards equation. We propose a stochastic extension for the empirical models that are typically employed to close the Richards equations. This is achieved by treating the soil parameters in...

Location and context – analysis of spatial inequalities at different geographical scales.: Deliverable 5.3

Resituating the Local in Cohesion and Territorial Development.

Evolution of dispersion in the melt compounding of a model polymer nanocomposite system: A multi-scale study

We investigate the morphological development of polystyrene (PS)-C ₆₀ nanocomposites along the length of a prototype co-rotating twin-screw extruder with sampling capabilities. The effects of C ₆₀ concentration and output on the morphological evolution along the extruder are studied employing a suite of characterization...

A multigrid multilevel Monte Carlo method for transport in the Darcy–Stokes system

A multilevel Monte Carlo (MLMC) method for Uncertainty Quantification (UQ) of advection-dominated contaminant transport in a coupled Darcy–Stokes flow system is described. In particular, we focus on high-dimensional epistemic uncertainty due to an unknown permeability field in the Darcy domain that is modelled as a lognormal random field....

A Journey along the Extruder with Polystyrene: C60 Nanocomposites: Convergence of Feeding Formulations into a Similar Nanomorphology

We investigated the effect of the feeding formulation (premixed powders of pure components versus solvent-blended mixture) of polystyrene–C60 composites on the dispersion and reagglomeration phenomena developing along the barrel of a twin-screw extruder. The dispersion of C60 in the PS matrix is studied over different length scales using a...

Multigrid method for nonlinear poroelasticity equations

In this study, a nonlinear multigrid method is applied for solving the system of incompressible poroelasticity equations considering nonlinear hydraulic conductivity. For the unsteady problem, an additional artificial term is utilized to stabilize the solutions when the equations are discretized on collocated grids. We employ two nonlinear...

Micro-fabricated channel with ultra-thin yet ultra-strong windows enables electron microscopy under 4-bar pressure

Transmission electron microscopy (TEM) of (de-)hydrogenation reactions is crucial to characterize efficiency of hydrogen storage materials. The nanoreactor, a micromachined channel with 15-nm-thick windows, effectively confines the gas flow to an electron-transparent chamber during TEM of reactions. Realistic experiments require very high...

Addressing complexity aspects in conceptual ship design: A systems engineering approach

Accuracy Measures and Fourier Analysis for the Full Multigrid Algorithm

The full multigrid (FMG) algorithm is often claimed to achieve so-called discretization-level accuracy. In this paper, this notion is formalized by defining a worst-case relative accuracy measure, denoted ElFMG, which compares the total error of the l-level FMG solution against the inherent discretization error. This measure can be used for...

On a decoupled algorithm for poroelasticity and its resolution by multigrid

In this work, we present a robust and efficient multigrid solver for a reformulated version of the system of poroelasticity equations. The reformulation enables us to treat the system in a decoupled fashion. It is sufficient to choose a highly efficient multigrid method for a scalar Poisson type equation for the overall solution of this...

On a decoupled algorithm for poroelasticity and its resolution by multigrid

In this work, we present a robust and efficient multigrid solver for a reformulated version of the system of poroelasticity equations. The reformulation enables us to treat the system in a decoupled fashion. It is sufficient to choose a highly efficient multigrid method for a scalar Poisson type equation for the overall solution of this...