SEG Technical Program Expanded Abstracts 2013, 2013
ABSTRACT The Spectral Element Method (SEM), widely used in engineering sciences but almost unknow... more ABSTRACT The Spectral Element Method (SEM), widely used in engineering sciences but almost unknown in Oil&Gas exploration, is a numerical technique for large scale and multi-physics simulations. SEM is an h-p approximation of the problem solution that allows a quasi-optimal distribution of computational points on unstructured grids so as to reduce both memory usage and processing time. Thus, when accuracy is mandatory in complex 3D geometries, SEM becomes an excellent alternative to Finite Elements (FE) and Finite Differences (FD). Its implementation on the elemental domain discretization, taking advantage of data locality, presents perspectives of significant speedups on acceleration architectures. Our SEM application is designed for the simulation of acoustic/elastic waves traveling across 3D subsurface models with liquid-solid interfaces and is capable of dealing with anisotropic and non-linear solid materials. In this work, some details of our SEM implementation and its HPC infrastructure are illustrated together with some simulation results.
Accelerator Driven Systems (ADS) are extensively investigated for the transmutation of high-level... more Accelerator Driven Systems (ADS) are extensively investigated for the transmutation of high-level nuclear waste within many worldwide research programs. The first advanced design of an ADS system is currently developed in SCK•CEN, Mol, Belgium: the Multi-purpose hYbrid Research Reactor for High-tech Applications (MYRRHA). Many European research programs support the design of MYRRHA. In the framework of the Euratom project ‘Thermal Hydraulics of Innovative nuclear Systems (THINS)’ a liquid-metal free-surface experiment is performed at the Karlsruhe Liquid Metal Laboratory (KALLA) of Karlsruhe Institute of Technology (KIT). The experiment investigates a full-scale model of the concentric free-surface spallation target of MYRRHA using Lead Bismuth Eutectic (LBE) as coolant. In parallel, numerical free surface models are developed and tested which are reviewed in the article. A volume-of-fluid method, a moving mesh model, a free surface model combining the Level-Set method with Large-Ed...
Therefore, accurate prediction of sloshing loads is of main concern for the design stage of ship ... more Therefore, accurate prediction of sloshing loads is of main concern for the design stage of ship tanks. In most of the cases, the dynamic interaction between the structural vibrations and the ow eld is neglected, i.e. uid loads are determined by studying liquid sloshing in rigid tanks. However, the accuracy of this simpli ed analysis is questionable when dealing with lighter structures or high-strength structural steels. This latter case is of growing importance in current design practice [5, 8], and the modeling of uid-structure interaction is needed to understand the various associated hydroelastic phenomena and to assess the safety of the system.
<p>Convective rainfall events represent one of the most critical issues in urban areas, whe... more <p>Convective rainfall events represent one of the most critical issues in urban areas, where numerical weather prediction models are affected by a large uncertainty related to the short temporal and spatial scales involved, thus making early warning systems ineffective. Conversely, radar-based nowcasting models may be a useful tool to guarantee short-term forecasts, through the extrapolation of most recent properties in observed precipitation fields, for lead times ranging from minutes to few hours.</p><p>In this study we develop a procedure for merging relevant information from two radar products with different resolutions and scales: (i) high-resolution observations retrieved by an X-band weather radar in a small domain (the metropolitan area of Cagliari, located in Sardinia, Italy), and (ii) the mosaic data provided by the Italian Civil Protection national radar network (the whole region of Sardinia). Specifically, we here adapt some STEPS procedures to merge the large-scale advection from the latter radar network, and the small-scale statistical properties for the former X-band weather radar. We thus combine the corresponding forecasts preserving the higher resolution scale. In details, for each time step we (i) evaluate the power spectra of the two forecasts (ii) merge the two spectra taking the power of the large (small) frequencies from the high (low) resolution data spectrum and (iii) achieve optimal downscaling by reconstructing the high-resolution nowcast from the blend of the two spectra.</p>
2020 2nd IEEE International Conference on Industrial Electronics for Sustainable Energy Systems (IESES)
The application of load disaggregation techniques based on neural networks is often limited to us... more The application of load disaggregation techniques based on neural networks is often limited to users included in the training dataset. A methodology based on techniques typical of the semantic segmentation of images has been proposed for this task, which allows to obtain a high accuracy and good generalization. We introduce here a novel data augmentation technique for improving forecasts for unmonitored houses that does not require any interaction with the user, nor further measurements of consumption of household appliances.
In this report we present the technical specification for the numerical model and the study of th... more In this report we present the technical specification for the numerical model and the study of the dynamic structural behaviour of the beam diluter elements (TPSG4 & 6) protecting the extraction septum magnets (MSE & MST) in the event of an asynchronous firing of the extraction kickers (MKE). The deposited energy densities, estimated by the high-energy particle transport code FLUKA, were converted to internal heat generation rates according to the time dependence of the extracted beam. The transient response to this thermal load was obtained by solving the power deposition and structural deformation problem by the spectral-element code ELSE.
The spectral element method (SEM) is a powerful numerical technique naturally suited for wave pro... more The spectral element method (SEM) is a powerful numerical technique naturally suited for wave propagation and dynamic soil-structure interaction (DSSI) analyses. A class of SEM has been widely used in the seismological field (local or global seismology) thanks to its capability of providing high accuracy and allowing the implementation of optimized parallel algorithms. We illustrate in this contribution how the SEM can be effectively used also for the numerical analysis of DSSI problems, with reference to the 3D seismic response of a railway viaduct in Italy. This numerical analysis includes the combined effect of: a) strong lateral variations of soil properties; b) topographic amplification; c) DSSI; d) spatial variation of earthquake ground motion in the structural response. Some hints on the work in progress to effectively handle nonlinear problems with SEM are also given.
The aim of the report is to gather some information on the transient Smoothed Particle Hydrodynam... more The aim of the report is to gather some information on the transient Smoothed Particle Hydrodynamics simulations of the CRS4 spallation target for ESS, run with the CRS4 in-house SPH code Armando. The problem is briefly described in terms of model, material and loading conditions. Some details on the simulation methods are given and the results are discussed, with focus on the splashing phenomenon. Table of
1 7 TeV proton beams from the LHC are ejected through a 600 m long beam dump transfer line vacuum... more 1 7 TeV proton beams from the LHC are ejected through a 600 m long beam dump transfer line vacuum chamber to a beam dump block. The dump block is contained within an inert gas-filled vessel to prevent a possible fire risk. The dump vessel and transfer line are separated by a 600 mm diameter window, which must withstand both the static pressure load and thermal shock from the passage of the LHC beam. In a previous paper (1) the functional requirements and conceptual design of this window were outlined. This paper describes the analysis leading to the final design of the window. The choice of materials is explained and tests performed on the prototype window are summarized. Abstract
The Smoothed Particle Hydrodynamics methodologies may be a useful numerical tool for the simulati... more The Smoothed Particle Hydrodynamics methodologies may be a useful numerical tool for the simulation of particle beam interaction with liquid targets and obstacles. ARMANDO code is a state of the art SPH code interfaced with FLUKA and capable to solve these problems. This report presents the basic theoretical elements behind the method, describes the most important aspects of the implementation and shows some simple examples.
Turbulence is of paramount importance in wildland fire propagation since it randomly transports t... more Turbulence is of paramount importance in wildland fire propagation since it randomly transports the hot air mass that can pre-heat and then ignite the area ahead the fire. This contributes to give a random character to the firefront position together with other phenomena as for example fire spotting, vegetation distribution (patchiness), gaseous combustion fluctuation, small-scale terrain elevation changes. Here only turbulence is considered. The level-set method is used to numerically describe the evolution of the fireline contour that is assumed to have a random motion because of turbulence. The progression of the combustion process is then described by a level-set contour distributed according to a weight function given by the probability density function of the air particles in turbulent motion. From the comparison between the ordinary and the randomized level-set methods, it emerges that the proposed modelling approach turns out to be suitable to simulate a moving firefront fed...
The Smoothed Particle Hydrodynamic (SPH) is a mesh-less method, it adopts a Lagrangian approach a... more The Smoothed Particle Hydrodynamic (SPH) is a mesh-less method, it adopts a Lagrangian approach and models the continuum as a set of mutually interacting particles that describe realistically and with good accuracy the motion of fluids, in particular when free surface conditions are present, without any limit on the density ratio. The fluid is treated as compressible and in our implementation this allows to simulate realistically the formation and propagation of acoustic pressure waves due to the interaction with a beam. The SPH approach, while rather new as an engineering tool, has already been applied to water wave breaking, dam collapse, water jets or impact of projectiles as referred in literature. It is not competitive with the traditional CFD methods when closed domains are analyzed, mainly due to relatively poor efficiency of the algorithm in a CPU architecture. The method is in fact well suited for massively parallel architectures. The recent interest and popularity of GPU m...
SEG Technical Program Expanded Abstracts 2013, 2013
ABSTRACT The Spectral Element Method (SEM), widely used in engineering sciences but almost unknow... more ABSTRACT The Spectral Element Method (SEM), widely used in engineering sciences but almost unknown in Oil&amp;Gas exploration, is a numerical technique for large scale and multi-physics simulations. SEM is an h-p approximation of the problem solution that allows a quasi-optimal distribution of computational points on unstructured grids so as to reduce both memory usage and processing time. Thus, when accuracy is mandatory in complex 3D geometries, SEM becomes an excellent alternative to Finite Elements (FE) and Finite Differences (FD). Its implementation on the elemental domain discretization, taking advantage of data locality, presents perspectives of significant speedups on acceleration architectures. Our SEM application is designed for the simulation of acoustic/elastic waves traveling across 3D subsurface models with liquid-solid interfaces and is capable of dealing with anisotropic and non-linear solid materials. In this work, some details of our SEM implementation and its HPC infrastructure are illustrated together with some simulation results.
Accelerator Driven Systems (ADS) are extensively investigated for the transmutation of high-level... more Accelerator Driven Systems (ADS) are extensively investigated for the transmutation of high-level nuclear waste within many worldwide research programs. The first advanced design of an ADS system is currently developed in SCK•CEN, Mol, Belgium: the Multi-purpose hYbrid Research Reactor for High-tech Applications (MYRRHA). Many European research programs support the design of MYRRHA. In the framework of the Euratom project ‘Thermal Hydraulics of Innovative nuclear Systems (THINS)’ a liquid-metal free-surface experiment is performed at the Karlsruhe Liquid Metal Laboratory (KALLA) of Karlsruhe Institute of Technology (KIT). The experiment investigates a full-scale model of the concentric free-surface spallation target of MYRRHA using Lead Bismuth Eutectic (LBE) as coolant. In parallel, numerical free surface models are developed and tested which are reviewed in the article. A volume-of-fluid method, a moving mesh model, a free surface model combining the Level-Set method with Large-Ed...
Therefore, accurate prediction of sloshing loads is of main concern for the design stage of ship ... more Therefore, accurate prediction of sloshing loads is of main concern for the design stage of ship tanks. In most of the cases, the dynamic interaction between the structural vibrations and the ow eld is neglected, i.e. uid loads are determined by studying liquid sloshing in rigid tanks. However, the accuracy of this simpli ed analysis is questionable when dealing with lighter structures or high-strength structural steels. This latter case is of growing importance in current design practice [5, 8], and the modeling of uid-structure interaction is needed to understand the various associated hydroelastic phenomena and to assess the safety of the system.
<p>Convective rainfall events represent one of the most critical issues in urban areas, whe... more <p>Convective rainfall events represent one of the most critical issues in urban areas, where numerical weather prediction models are affected by a large uncertainty related to the short temporal and spatial scales involved, thus making early warning systems ineffective. Conversely, radar-based nowcasting models may be a useful tool to guarantee short-term forecasts, through the extrapolation of most recent properties in observed precipitation fields, for lead times ranging from minutes to few hours.</p><p>In this study we develop a procedure for merging relevant information from two radar products with different resolutions and scales: (i) high-resolution observations retrieved by an X-band weather radar in a small domain (the metropolitan area of Cagliari, located in Sardinia, Italy), and (ii) the mosaic data provided by the Italian Civil Protection national radar network (the whole region of Sardinia). Specifically, we here adapt some STEPS procedures to merge the large-scale advection from the latter radar network, and the small-scale statistical properties for the former X-band weather radar. We thus combine the corresponding forecasts preserving the higher resolution scale. In details, for each time step we (i) evaluate the power spectra of the two forecasts (ii) merge the two spectra taking the power of the large (small) frequencies from the high (low) resolution data spectrum and (iii) achieve optimal downscaling by reconstructing the high-resolution nowcast from the blend of the two spectra.</p>
2020 2nd IEEE International Conference on Industrial Electronics for Sustainable Energy Systems (IESES)
The application of load disaggregation techniques based on neural networks is often limited to us... more The application of load disaggregation techniques based on neural networks is often limited to users included in the training dataset. A methodology based on techniques typical of the semantic segmentation of images has been proposed for this task, which allows to obtain a high accuracy and good generalization. We introduce here a novel data augmentation technique for improving forecasts for unmonitored houses that does not require any interaction with the user, nor further measurements of consumption of household appliances.
In this report we present the technical specification for the numerical model and the study of th... more In this report we present the technical specification for the numerical model and the study of the dynamic structural behaviour of the beam diluter elements (TPSG4 & 6) protecting the extraction septum magnets (MSE & MST) in the event of an asynchronous firing of the extraction kickers (MKE). The deposited energy densities, estimated by the high-energy particle transport code FLUKA, were converted to internal heat generation rates according to the time dependence of the extracted beam. The transient response to this thermal load was obtained by solving the power deposition and structural deformation problem by the spectral-element code ELSE.
The spectral element method (SEM) is a powerful numerical technique naturally suited for wave pro... more The spectral element method (SEM) is a powerful numerical technique naturally suited for wave propagation and dynamic soil-structure interaction (DSSI) analyses. A class of SEM has been widely used in the seismological field (local or global seismology) thanks to its capability of providing high accuracy and allowing the implementation of optimized parallel algorithms. We illustrate in this contribution how the SEM can be effectively used also for the numerical analysis of DSSI problems, with reference to the 3D seismic response of a railway viaduct in Italy. This numerical analysis includes the combined effect of: a) strong lateral variations of soil properties; b) topographic amplification; c) DSSI; d) spatial variation of earthquake ground motion in the structural response. Some hints on the work in progress to effectively handle nonlinear problems with SEM are also given.
The aim of the report is to gather some information on the transient Smoothed Particle Hydrodynam... more The aim of the report is to gather some information on the transient Smoothed Particle Hydrodynamics simulations of the CRS4 spallation target for ESS, run with the CRS4 in-house SPH code Armando. The problem is briefly described in terms of model, material and loading conditions. Some details on the simulation methods are given and the results are discussed, with focus on the splashing phenomenon. Table of
1 7 TeV proton beams from the LHC are ejected through a 600 m long beam dump transfer line vacuum... more 1 7 TeV proton beams from the LHC are ejected through a 600 m long beam dump transfer line vacuum chamber to a beam dump block. The dump block is contained within an inert gas-filled vessel to prevent a possible fire risk. The dump vessel and transfer line are separated by a 600 mm diameter window, which must withstand both the static pressure load and thermal shock from the passage of the LHC beam. In a previous paper (1) the functional requirements and conceptual design of this window were outlined. This paper describes the analysis leading to the final design of the window. The choice of materials is explained and tests performed on the prototype window are summarized. Abstract
The Smoothed Particle Hydrodynamics methodologies may be a useful numerical tool for the simulati... more The Smoothed Particle Hydrodynamics methodologies may be a useful numerical tool for the simulation of particle beam interaction with liquid targets and obstacles. ARMANDO code is a state of the art SPH code interfaced with FLUKA and capable to solve these problems. This report presents the basic theoretical elements behind the method, describes the most important aspects of the implementation and shows some simple examples.
Turbulence is of paramount importance in wildland fire propagation since it randomly transports t... more Turbulence is of paramount importance in wildland fire propagation since it randomly transports the hot air mass that can pre-heat and then ignite the area ahead the fire. This contributes to give a random character to the firefront position together with other phenomena as for example fire spotting, vegetation distribution (patchiness), gaseous combustion fluctuation, small-scale terrain elevation changes. Here only turbulence is considered. The level-set method is used to numerically describe the evolution of the fireline contour that is assumed to have a random motion because of turbulence. The progression of the combustion process is then described by a level-set contour distributed according to a weight function given by the probability density function of the air particles in turbulent motion. From the comparison between the ordinary and the randomized level-set methods, it emerges that the proposed modelling approach turns out to be suitable to simulate a moving firefront fed...
The Smoothed Particle Hydrodynamic (SPH) is a mesh-less method, it adopts a Lagrangian approach a... more The Smoothed Particle Hydrodynamic (SPH) is a mesh-less method, it adopts a Lagrangian approach and models the continuum as a set of mutually interacting particles that describe realistically and with good accuracy the motion of fluids, in particular when free surface conditions are present, without any limit on the density ratio. The fluid is treated as compressible and in our implementation this allows to simulate realistically the formation and propagation of acoustic pressure waves due to the interaction with a beam. The SPH approach, while rather new as an engineering tool, has already been applied to water wave breaking, dam collapse, water jets or impact of projectiles as referred in literature. It is not competitive with the traditional CFD methods when closed domains are analyzed, mainly due to relatively poor efficiency of the algorithm in a CPU architecture. The method is in fact well suited for massively parallel architectures. The recent interest and popularity of GPU m...
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