A 3D time-dependent backward erosion piping model

Backward erosion piping (BEP) is a failure mechanism of hydraulic structures like dams and levees on cohesionless foundations subjected to seepage flows. This article models the time-dependent development of BEP using numerical simulation of the erosion process. A 3-dimensional finite element equilibrium BEP model is extended with a...

Preloading of four-legged jack-ups in clay: Geotechnical time effects and fulfilment of preloading criteria

Presented here is a numerical study on the preloading of four-legged jack-ups, such as those commonly employed in the construction of offshore wind farms. The need for reducing jack-up installation time is particularly felt within the offshore industry, especially when multiple preloading cycles are necessary in clayey soils to fulfil given...

Unisolvence of Symmetric Node Patterns for Polynomial Spaces on the Simplex

Finite elements with polynomial basis functions on the simplex with a symmetric distribution of nodes should have a unique polynomial representation. Unisolvence not only requires that the number of nodes equals the number of independent polynomials spanning a polynomial space of a given degree, but also that the Vandermonde matrix...

Numerical interpretation of regressive localized internal erosion in a real-scale levee physical model

This paper presents the numerical interpretation of a recent experiment on a real-scale levee physical model, in order to investigate the process of Backward Erosion Piping (BEP) and validate a recently proposed finite element formulation able to model both the simultaneous processes observed in backward erosion piping, i.e. the propagation of...

Numerical Approaches for Investigating Quasiconvexity in the Context of Morrey’s Conjecture

Deciding whether a given function is quasiconvex is generally a difficult task. Here, we discuss a number of numerical approaches that can be used in the search for a counterexample to the quasiconvexity of a given function W. We will demonstrate these methods using the planar isotropic rank-one convex function Wmagic+(F)=λmaxλmin-logλmaxλmin...

More Continuous Mass-Lumped Triangular Finite Elements

When solving the wave equation with finite elements, mass lumping allows for explicit time stepping, avoiding the cost of a lower-upper decomposition of the large sparse mass matrix. Mass lumping on the reference element amounts to numerical quadrature. The weights should be positive for stable time stepping and preserve numerical accuracy....

A monolithic finite element formulation for the hydroelastic analysis of very large floating structures

In this work we present a novel monolithic Finite Element method for the hydroelastic analysis of very large floating structures (VLFS) with arbitrary shapes that is stable, energy conserving, and overcomes the need of an iterative algorithm. The new formulation enables a fully monolithic solution of the linear free-surface flow, described by...

High-precision Versatile Ultrasonic Flow Meters Based on Matrix Transducer Arrays

Ultrasonic flow meters are widely applied to measure flow in a variety of applications. The vast majority of ultrasonic flow meters are based on the measurement of the transit time of an acoustic pulse through the fluid. This can either be done in-line, by inserting a spool piece with ultrasonic transducers into the pipe carrying the fluid, or...

Displacement-based formulation of Koiter's method: Application to multi-modal post-buckling finite element analysis of plates

Koiter's asymptotic method enables the calculation and deep understanding of the initial post-buckling behaviour of thin-walled structures. For the single-mode asymptotic analysis, Budiansky (1974) presented a clear and general formulation for Koiter's method, based on the expansion of the total potential energy function. The formulation from...

LEOPART: A particle library for FENICS

This paper introduces LEOPART, an add-on for the open-source finite element software library FENICS to seamlessly integrate Lagrangian particle functionality with (Eulerian) mesh-based finite element (FE) approaches. LEOPART- which is so much as to say: ‘Lagrangian–Eulerian on Particles’ - contains tools for efficient, accurate and scalable...

A transient backward erosion piping model based on laminar flow transport equations

Backward erosion piping is an internal erosion process, which compromises the stability of water retaining structures such as dams and levees. In this paper, we propose a numerical solution that combines a 2D Darcy groundwater solution with Exner's 1D sediment transport mass conservation equation. As an estimate of sediment transport, we...

Isogeometric analysis of linear free-surface potential flow

This paper presents a novel variational formulation to simulate linear free-surface flow. The variational formulation is suitable for higher-order finite elements and higher-order and higher-continuity shape functions as employed in Isogeometric Analysis (IGA). The novel formulation combines the interior and free-surface problems in one...

Toward free-surface flow simulations with correct energy evolution: An isogeometric level-set approach with monolithic time-integration

This paper presents a new monolithic free-surface formulation that exhibits correct kinetic and potential energy behavior. We focus in particular on the temporal energy behavior of two-fluids flow with varying densities. Correct energy behavior here means that the actual energy evolution of the numerical solution matches the evolution as...

A hybridized discontinuous Galerkin framework for high-order particle–mesh operator splitting of the incompressible Navier–Stokes equations

A generic particle–mesh method using a hybridized discontinuous Galerkin (HDG) framework is presented and validated for the solution of the incompressible Navier–Stokes equations. Building upon particle-in-cell concepts, the method is formulated in terms of an operator splitting technique in which Lagrangian particles are used to discretize...

Sequential reduction of slope stability uncertainty based on temporal hydraulic measurements via the ensemble Kalman filter

A data assimilation framework, utilising measurements of pore water pressure to sequentially improve the estimation of soil hydraulic parameters and, in turn, the prediction of slope stability, is proposed. Its effectiveness is demonstrated for an idealised numerical example involving the spatial variability of saturated hydraulic...

Computational Time Reversal for NDT Applications Using Experimental Data

A model-based non destructive testing (NDT) method is proposed for damage identification in elastic structures, incorporating computational time reversal (TR) analysis. Identification is performed by advancing elastic wave signals, measured at discrete sensor locations, backward in time. In contrast to a previous study, which was purely...

Design and optimization method for 3D printed carbon reinforced aircraft components

Recent developments in the field of plastic additive manufacturing have seen the introduction of carbon fibres in printed products. These fibres improve the strength and stiffness of the thermoplastic based components. Two approaches are currently seen, the very short fibre embedded in the printing filament and continuous fibres, where the...

The role of continuity in residual-based variational multiscale modeling of turbulence

This paper examines the role of continuity of the basis in the computation of turbulent flows. We compare standard finite elements and non-uniform rational B-splines (NURBS) discretizations that are employed in Isogeometric Analysis (Hughes et al. in Comput Methods Appl Mech Eng, 194:4135–4195, 2005). We make use of quadratic discretizations...