35,879 research outputs found
Fluid-Structure Interaction Simulation of a Coriolis Mass Flowmeter using a Lattice Boltzmann Method
In this paper we use a fluid-structure interaction (FSI) approach to simulate
a Coriolis mass flowmeter (CMF). The fluid dynamics are calculated by the open
source framework OpenLB, based on the lattice Boltzmann method (LBM). For the
structural dynamics we employ the open source software Elmer, an implementation
of the finite element method (FEM). A staggered coupling approach between the
two software packages is presented. The finite element mesh is created by the
mesh generator Gmsh to ensure a complete open source workflow. The Eigenmodes
of the CMF, which are calculated by modal analysis are compared with
measurement data. Using the estimated excitation frequency, a fully coupled,
partitioned, FSI simulation is applied to simulate the phase shift of the
investigated CMF design. The calculated phaseshift values are in good agreement
to the measurement data and verify the suitability of the model to numerically
describe the working principle of a CMF
2D approach for modelling self-potential anomalies. Application to synthetic and real data
The aim of this work is to present a 2-D Matlab code based on the finite element method
for providing numerical modelling of both groundwater flow and self-potential signals.
The distribution of the self-potential is obtained by starting with the solution of the
groundwater flow, then computing the source current density, and finally calculating
the electrical potential. The reliability of the algorithm is tested with synthetic case
studies in order to simulate both the electric field resulting from the existence of a leak
in the dam and SP signals associated with a pumping test in an unconfined aquifer. In
addition, the algorithm was applied to field data for the localization of piping sinkholes.
The results show that the outputs of the algorithm yielded satisfactory solutions, which
are in good agreement with those of previous studies and field investigations. In details,
the synthetic data and SP anomalies calculated by using the code are very close in
terms of sign and magnitude, while real data tests clearly indicated that the computed
SP signals were found to be consistent with the measured values
Efficient solution of 3D electromagnetic eddy-current problems within the finite volume framework of OpenFOAM
Eddy-current problems occur in a wide range of industrial and metallurgical
applications where conducting material is processed inductively. Motivated by
realising coupled multi-physics simulations, we present a new method for the
solution of such problems in the finite volume framework of foam-extend, an
extended version of the very popular OpenFOAM software. The numerical procedure
involves a semi-coupled multi-mesh approach to solve Maxwell's equations for
non-magnetic materials by means of the Coulomb gauged magnetic vector potential
and the electric scalar potential. The concept is further extended on the basis
of the impressed and reduced magnetic vector potential and its usage in
accordance with Biot-Savart's law to achieve a very efficient overall modelling
even for complex three-dimensional geometries. Moreover, we present a special
discretisation scheme to account for possible discontinuities in the electrical
conductivity. To complement our numerical method, an extensive validation is
completing the paper, which provides insight into the behaviour and the
potential of our approach.Comment: 47 pages, improved figures, updated references, fixed typos, reverse
phase shift, consistent use of inner produc
Exploring the concept of interaction computing through the discrete algebraic analysis of the BelousovâZhabotinsky reaction
Interaction computing (IC) aims to map the properties of integrable low-dimensional non-linear dynamical systems to the discrete domain of finite-state automata in an attempt to reproduce in software the self-organizing and dynamically stable properties of sub-cellular biochemical systems. As the work reported in this paper is still at the early stages of theory development it focuses on the analysis of a particularly simple chemical oscillator, the Belousov-Zhabotinsky (BZ) reaction. After retracing the rationale for IC developed over the past several years from the physical, biological, mathematical, and computer science points of view, the paper presents an elementary discussion of the Krohn-Rhodes decomposition of finite-state automata, including the holonomy decomposition of a simple automaton, and of its interpretation as an abstract positional number system. The method is then applied to the analysis of the algebraic properties of discrete finite-state automata derived from a simplified Petri net model of the BZ reaction. In the simplest possible and symmetrical case the corresponding automaton is, not surprisingly, found to contain exclusively cyclic groups. In a second, asymmetrical case, the decomposition is much more complex and includes five different simple non-abelian groups whose potential relevance arises from their ability to encode functionally complete algebras. The possible computational relevance of these findings is discussed and possible conclusions are drawn
Electromagnetic modelling and simulation of a high-frequency ground penetrating radar antenna over a concrete cell with steel rods
This work focuses on the electromagnetic modelling and simulation of a highfrequency
Ground-Penetrating Radar (GPR) antenna over a concrete cell with
reinforcing elements. The development of realistic electromagnetic models of GPR
antennas is crucial for accurately predicting GPR responses and for designing
new antennas. We used commercial software implementing the Finite-Integration
technique (CST Microwave Studio) to create a model that is representative of a
1.5 GHz Geophysical Survey Systems, Inc. antenna, by exploiting information
published in the literature (namely, in the PhD Thesis of Dr Craig Warren); our
CST model was validated, in a previous work, by comparisons with FiniteDifference
Time-Domain results and with experimental data, with very good
agreement, showing that the software we used is suitable for the simulation of
antennas in the presence of targets in the near field. In the current paper, we
firstly describe in detail how the CST model of the antenna was implemented;
subsequently, we present new results calculated with the antenna over a
reinforced-concrete cell. Such cell is one of the reference scenarios included in
the Open Database of Radargrams of COST Action TU1208 âCivil engineering
applications of Ground Penetrating Radarâ and hosts five circular-section steel
rods, having different diameters, embedded at different depths into the concrete.
Comparisons with a simpler model, where the physical structure of the antenna
is not taken into account, are carried out; the significant differences between the
results of the realistic model and the results of the simplified model confirm the
importance of including accurate models of the actual antennas in GPR
simulations; they also emphasize how salient it is to remove antenna effects as a
pre-processing step of experimental GPR data. The simulation results of the
antenna over the concrete cell presented in this paper are attached to the paper
as âSupplementary materials.
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