... VS, Matyash, K., Schneider, R. & Fehske, H., ... more ... VS, Matyash, K., Schneider, R. & Fehske, H., Comparative study of semiclassical ap-proaches to quantum dynam-ics 8 (2009) 1155 Serra, TR, see Tabak, BM 8 (2009) 1121 Sever, R., see Arda, A. 4 (2009) 651 Sever, R., see Ikhdair, SM 3 (2009) 361 Sezgin, F., Geometric ...
We present quantum Lattice Boltzmann simulations of the Dirac equation for quantum-relativistic p... more We present quantum Lattice Boltzmann simulations of the Dirac equation for quantum-relativistic particles with random mass. By choosing zero-average random mass fluctuation, the simulations show evidence of localization and ultra-slow Sinai diffusion, due to the interference of oppositely propagating branches of the quantum wavefunction which result from random sign changes of the mass around a zero-mean. The present results indicate that the quantum lattice Boltzmann scheme may offer a viable tool for the numerical simulation of quantum-relativistic transport phenomena in topological materials.
A generalization of mesoscopic Lattice-Boltzmann models aimed at describing flows with solid/liqu... more A generalization of mesoscopic Lattice-Boltzmann models aimed at describing flows with solid/liquid phase transitions is presented. It exhibits lower computational costs with respect to the numerical schemes resulting from differential models. Moreover it is suitable to describe chaotic motions in the mushy zone.
Data-Based Applications.- to OGSA-DAI Services.- Using OGSA-DQP to Support Scientific Application... more Data-Based Applications.- to OGSA-DAI Services.- Using OGSA-DQP to Support Scientific Applications for the Grid.- Mobile Agent-Based Service Provision in Distributed Data Archives.- A Proxy Service for the xrootd Data Server.- A Flexible Two-Level I/O Architecture for Grids.- Data Driven Infrastructure and Policy Selection to Enhance Scientific Applications in Grid.- BioApplications.- Modelling a Protein Structure Comparison Application on the Grid Using PROTEUS.- Grid Services Complemented by Domain Ontology Supporting Biomedical Community.- Applications Architecture, Frameworks and Models.- A Generic Architecture for Sensor Data Integration with the Grid.- Embarrassingly Distributed and Master-Worker Paradigms on the Grid.- A Framework for the Design and Reuse of Grid Workflows.- Towards Peer-to-Peer Access Grid.- A Service Oriented Architecture for Integration of Fault Diagnostics.- GAM: A Grid Awareness Model for Grid Environments.- Accounting and Market-Based Architecture.- Grid Accounting Service Infrastructure for Service-Oriented Grid Computing Systems.- Mercatus: A Toolkit for the Simulation of Market-Based Resource Allocation Protocols in Grids.- Resource and Information Management in Grid.- A Resource Monitoring and Management Middleware Infrastructure for Semantic Resource Grid.- A Service-Oriented Framework for Traffic Information Grid.
We present a Polar Coordinate Lattice Boltzmann kinetic model for compressible flows. A method to... more We present a Polar Coordinate Lattice Boltzmann kinetic model for compressible flows. A method to recover the continuum distribution function from the discrete distribution function is indicated. Within the model, a hybrid scheme being similar to, but different from, the operatorsplitting is proposed. The temporal evolution is calculated analytically and the convection term is solved via a Modified Warming-Beam (MWB) scheme. Within the MWB scheme a suitable switch function is introduced. The current model works not only for subsonic flows but also for supersonic flows. It is validated and verified via the following well-known benchmark tests: (i) the rotational flow, (ii) the stable shock tube problem, (iii) the Richtmyer-Meshkov (RM) instability, (iv) the Kelvin-Helmholtz instability. As an original application, we studied the non-equilibrium characteristics of the system around three kinds of interfaces, the shock wave, the rarefaction wave and the material interface, for two specific cases. In one of the two cases, the material interface is initially perturbed and consequently the RM instability occurs. It is found that, the macroscopic effects due to deviating from thermodynamic equilibrium around the material interface differ significantly from those around the mechanical interfaces. The initial perturbation at the material interface enhances the coupling of molecular motions in different degrees of freedom. The amplitude of deviation from thermodynamic equilibrium around the shock wave is much higher than those around the rarefaction wave and material interface. By comparing each component of the high-order moments and its value in equilibrium, we can draw qualitatively the main behavior of the actual distribution function. These results deepen our understanding of the mechanical and material interfaces from a more fundamental level, which is indicative for constructing macroscopic models and other kinds of kinetic models.
Thermal and mechanical energy storage is pivotal for the effective exploitation of renewable ener... more Thermal and mechanical energy storage is pivotal for the effective exploitation of renewable energy sources, thus fostering the transition to a sustainable economy. Hydrogen-based systems are among the most promising solutions for electrical energy storage. However, several technical and economic barriers (e.g., high costs, low energy and power density, advanced material requirements) still hinder the diffusion of such solutions. Similarly, the realization of latent heat storages through phase change materials is particularly attractive because it provides high energy density in addition to allowing for the storage of the heat of fusion at a (nearly) constant temperature. In this paper, we posit the challenge to couple a metal hydride H2 canister with a latent heat storage, in order to improve the overall power density and realize a passive control of the system temperature. A highly flexible numerical solver based on a hybrid Lattice Boltzmann Phase-Field (LB-PF) algorithm is devel...
It is shown that the combined use of a mesoscopic lattice Boltzmann solver with finite-volume tec... more It is shown that the combined use of a mesoscopic lattice Boltzmann solver with finite-volume techniques, both enriched with local-refinement (multiscale) capabilities, permits to describe transport phenomena at fluid-solid interfaces to a degree of detail which may help dispensing with empirical correlations.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2019
We outline the main ideas behind the numerical modelling of soft flowing crystals, paying special... more We outline the main ideas behind the numerical modelling of soft flowing crystals, paying special attention to their application to microfluidic devices for the design of novel mesoscale porous materials. This article is part of the theme issue ‘Multiscale modelling, simulation and computing: from the desktop to the exascale’.
Multiscale Lattice Boltzmann schemes for fluid dynamic applications are described and their effic... more Multiscale Lattice Boltzmann schemes for fluid dynamic applications are described and their efficiency is discussed in terms of accuracy and computational cost. A novel application to axial compressor flows is proposed. Conditions on periodic boundaries have been appropriately developed. Our preliminary results indicate that these schemes hold good potential for the simulation of fluid flows in turbomachines.
Fundamental Problematic Issues in Turbulence, 1999
ABSTRACT We present a study of intermittency in a channel, i.e. in a inhomogeneous nonisotropic f... more ABSTRACT We present a study of intermittency in a channel, i.e. in a inhomogeneous nonisotropic flow. Scaling exponents of longitudinal streamwise structure functions, ζ p , are used as quantitative indicators of intermittency. We find that, near the core of the channel, the value of ζ p are consistent with homogeneous/isotropic values. Near the boundaries intermittency is much higher, approaching passive scalar values.
The entropy maximum approach to constructing equilibria in lattice kinetic equations is revisited... more The entropy maximum approach to constructing equilibria in lattice kinetic equations is revisited. For a suitable entropy function, we derive explicitly the hydrodynamic local equilibrium, prove the H theorem for lattice Bhatnagar-Gross-Krook models, and develop a systematic method to account for additional constraints. [S0031-9007(98)06482-5]
A Lattice Boltzmann formulation for relativistic fluids is presented and numerically verified thr... more A Lattice Boltzmann formulation for relativistic fluids is presented and numerically verified through quantitative comparison with recent hydrodynamic simulations of relativistic shock-wave propagation in viscous quark-gluon plasmas. This formulation opens up the possibility of exporting the main advantages of Lattice Boltzmann methods to the relativistic context, which seems particularly useful for the simulation of relativistic fluids in complicated geometries.
Space-time patterns of wall shear stress (WSS) resulting from the numerical simulation of pulsati... more Space-time patterns of wall shear stress (WSS) resulting from the numerical simulation of pulsating hemodynamic flows in semicoronal domains are analyzed, in the case of both regular semicoronal domains and semicoronal domains with bumpy insertions, mimicking aneurysm-like geometries. A new family of cardiovascular risk indicators, which we name three-band diagrams (TBDs), are introduced, as a sensible generalization of the two standard indicators, i.e., the time-averaged WSS and the oscillatory shear index. TBDs provide a handy access to additional information contained in the dynamic structure of the WSS signal as a function of the physiological risk threshold, thereby allowing a quick visual assessment of the risk sensitivity to individual fluctuations of the physiological risk thresholds. Due to its generality, TBD analysis is expected to prove useful for a wide host of applications in science, engineering, and medicine, where risk assessment plays a central role.
The effects of mid-range repulsion in Lattice Boltzmann models on the coalescence/breakup behavio... more The effects of mid-range repulsion in Lattice Boltzmann models on the coalescence/breakup behaviour of single-component, non-ideal fluids are investigated. It is found that mid-range repulsive interactions allow the formation of spray-like, multi-droplet configurations, with droplet size directly related to the strength of the repulsive interaction. The simulations show that just a tiny ten-percent of mid-range repulsive pseudo-energy can boost the surface/volume ratio of the phaseseparated fluid by nearly two orders of magnitude. Drawing upon a formal analogy with magnetic Ising systems, a pseudo-potential energy is defined, which is found to behave like a quasi-conserved quantity for most of the time-evolution. This offers a useful quantitative indicator of the stability of the various configurations, thus helping the task of their interpretation and classification. The present approach appears to be a promising tool for the computational modelling of complex flow phenomena, such as atomization, spray formation and micro-emulsions, break-up phenomena and possibly glassy-like systems as well.
Taking advantage of a closed-form generalized Maxwell distribution function ͓P. Asinari and I. V.... more Taking advantage of a closed-form generalized Maxwell distribution function ͓P. Asinari and I. V. Karlin, Phys. Rev. E 79, 036703 ͑2009͔͒ and splitting the relaxation to the equilibrium in two steps, an entropic quasiequilibrium ͑EQE͒ kinetic model is proposed for the simulation of low Mach number flows, which enjoys both the H theorem and a free-tunable parameter for controlling the bulk viscosity in such a way as to enhance numerical stability in the incompressible flow limit. Moreover, the proposed model admits a simplification based on a proper expansion in the low Mach number limit ͑LQE model͒. The lattice Boltzmann implementation of both the EQE and LQE is as simple as that of the standard lattice Bhatnagar-Gross-Krook ͑LBGK͒ method, and practical details are reported. Extensive numerical testing with the lid driven cavity flow in two dimensions is presented in order to verify the enhancement of the stability region. The proposed models achieve the same accuracy as the LBGK method with much rougher meshes, leading to an effective computational speed-up of almost three times for EQE and of more than four times for the LQE. Three-dimensional extension of EQE and LQE is also discussed.
... VS, Matyash, K., Schneider, R. & Fehske, H., ... more ... VS, Matyash, K., Schneider, R. & Fehske, H., Comparative study of semiclassical ap-proaches to quantum dynam-ics 8 (2009) 1155 Serra, TR, see Tabak, BM 8 (2009) 1121 Sever, R., see Arda, A. 4 (2009) 651 Sever, R., see Ikhdair, SM 3 (2009) 361 Sezgin, F., Geometric ...
We present quantum Lattice Boltzmann simulations of the Dirac equation for quantum-relativistic p... more We present quantum Lattice Boltzmann simulations of the Dirac equation for quantum-relativistic particles with random mass. By choosing zero-average random mass fluctuation, the simulations show evidence of localization and ultra-slow Sinai diffusion, due to the interference of oppositely propagating branches of the quantum wavefunction which result from random sign changes of the mass around a zero-mean. The present results indicate that the quantum lattice Boltzmann scheme may offer a viable tool for the numerical simulation of quantum-relativistic transport phenomena in topological materials.
A generalization of mesoscopic Lattice-Boltzmann models aimed at describing flows with solid/liqu... more A generalization of mesoscopic Lattice-Boltzmann models aimed at describing flows with solid/liquid phase transitions is presented. It exhibits lower computational costs with respect to the numerical schemes resulting from differential models. Moreover it is suitable to describe chaotic motions in the mushy zone.
Data-Based Applications.- to OGSA-DAI Services.- Using OGSA-DQP to Support Scientific Application... more Data-Based Applications.- to OGSA-DAI Services.- Using OGSA-DQP to Support Scientific Applications for the Grid.- Mobile Agent-Based Service Provision in Distributed Data Archives.- A Proxy Service for the xrootd Data Server.- A Flexible Two-Level I/O Architecture for Grids.- Data Driven Infrastructure and Policy Selection to Enhance Scientific Applications in Grid.- BioApplications.- Modelling a Protein Structure Comparison Application on the Grid Using PROTEUS.- Grid Services Complemented by Domain Ontology Supporting Biomedical Community.- Applications Architecture, Frameworks and Models.- A Generic Architecture for Sensor Data Integration with the Grid.- Embarrassingly Distributed and Master-Worker Paradigms on the Grid.- A Framework for the Design and Reuse of Grid Workflows.- Towards Peer-to-Peer Access Grid.- A Service Oriented Architecture for Integration of Fault Diagnostics.- GAM: A Grid Awareness Model for Grid Environments.- Accounting and Market-Based Architecture.- Grid Accounting Service Infrastructure for Service-Oriented Grid Computing Systems.- Mercatus: A Toolkit for the Simulation of Market-Based Resource Allocation Protocols in Grids.- Resource and Information Management in Grid.- A Resource Monitoring and Management Middleware Infrastructure for Semantic Resource Grid.- A Service-Oriented Framework for Traffic Information Grid.
We present a Polar Coordinate Lattice Boltzmann kinetic model for compressible flows. A method to... more We present a Polar Coordinate Lattice Boltzmann kinetic model for compressible flows. A method to recover the continuum distribution function from the discrete distribution function is indicated. Within the model, a hybrid scheme being similar to, but different from, the operatorsplitting is proposed. The temporal evolution is calculated analytically and the convection term is solved via a Modified Warming-Beam (MWB) scheme. Within the MWB scheme a suitable switch function is introduced. The current model works not only for subsonic flows but also for supersonic flows. It is validated and verified via the following well-known benchmark tests: (i) the rotational flow, (ii) the stable shock tube problem, (iii) the Richtmyer-Meshkov (RM) instability, (iv) the Kelvin-Helmholtz instability. As an original application, we studied the non-equilibrium characteristics of the system around three kinds of interfaces, the shock wave, the rarefaction wave and the material interface, for two specific cases. In one of the two cases, the material interface is initially perturbed and consequently the RM instability occurs. It is found that, the macroscopic effects due to deviating from thermodynamic equilibrium around the material interface differ significantly from those around the mechanical interfaces. The initial perturbation at the material interface enhances the coupling of molecular motions in different degrees of freedom. The amplitude of deviation from thermodynamic equilibrium around the shock wave is much higher than those around the rarefaction wave and material interface. By comparing each component of the high-order moments and its value in equilibrium, we can draw qualitatively the main behavior of the actual distribution function. These results deepen our understanding of the mechanical and material interfaces from a more fundamental level, which is indicative for constructing macroscopic models and other kinds of kinetic models.
Thermal and mechanical energy storage is pivotal for the effective exploitation of renewable ener... more Thermal and mechanical energy storage is pivotal for the effective exploitation of renewable energy sources, thus fostering the transition to a sustainable economy. Hydrogen-based systems are among the most promising solutions for electrical energy storage. However, several technical and economic barriers (e.g., high costs, low energy and power density, advanced material requirements) still hinder the diffusion of such solutions. Similarly, the realization of latent heat storages through phase change materials is particularly attractive because it provides high energy density in addition to allowing for the storage of the heat of fusion at a (nearly) constant temperature. In this paper, we posit the challenge to couple a metal hydride H2 canister with a latent heat storage, in order to improve the overall power density and realize a passive control of the system temperature. A highly flexible numerical solver based on a hybrid Lattice Boltzmann Phase-Field (LB-PF) algorithm is devel...
It is shown that the combined use of a mesoscopic lattice Boltzmann solver with finite-volume tec... more It is shown that the combined use of a mesoscopic lattice Boltzmann solver with finite-volume techniques, both enriched with local-refinement (multiscale) capabilities, permits to describe transport phenomena at fluid-solid interfaces to a degree of detail which may help dispensing with empirical correlations.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2019
We outline the main ideas behind the numerical modelling of soft flowing crystals, paying special... more We outline the main ideas behind the numerical modelling of soft flowing crystals, paying special attention to their application to microfluidic devices for the design of novel mesoscale porous materials. This article is part of the theme issue ‘Multiscale modelling, simulation and computing: from the desktop to the exascale’.
Multiscale Lattice Boltzmann schemes for fluid dynamic applications are described and their effic... more Multiscale Lattice Boltzmann schemes for fluid dynamic applications are described and their efficiency is discussed in terms of accuracy and computational cost. A novel application to axial compressor flows is proposed. Conditions on periodic boundaries have been appropriately developed. Our preliminary results indicate that these schemes hold good potential for the simulation of fluid flows in turbomachines.
Fundamental Problematic Issues in Turbulence, 1999
ABSTRACT We present a study of intermittency in a channel, i.e. in a inhomogeneous nonisotropic f... more ABSTRACT We present a study of intermittency in a channel, i.e. in a inhomogeneous nonisotropic flow. Scaling exponents of longitudinal streamwise structure functions, ζ p , are used as quantitative indicators of intermittency. We find that, near the core of the channel, the value of ζ p are consistent with homogeneous/isotropic values. Near the boundaries intermittency is much higher, approaching passive scalar values.
The entropy maximum approach to constructing equilibria in lattice kinetic equations is revisited... more The entropy maximum approach to constructing equilibria in lattice kinetic equations is revisited. For a suitable entropy function, we derive explicitly the hydrodynamic local equilibrium, prove the H theorem for lattice Bhatnagar-Gross-Krook models, and develop a systematic method to account for additional constraints. [S0031-9007(98)06482-5]
A Lattice Boltzmann formulation for relativistic fluids is presented and numerically verified thr... more A Lattice Boltzmann formulation for relativistic fluids is presented and numerically verified through quantitative comparison with recent hydrodynamic simulations of relativistic shock-wave propagation in viscous quark-gluon plasmas. This formulation opens up the possibility of exporting the main advantages of Lattice Boltzmann methods to the relativistic context, which seems particularly useful for the simulation of relativistic fluids in complicated geometries.
Space-time patterns of wall shear stress (WSS) resulting from the numerical simulation of pulsati... more Space-time patterns of wall shear stress (WSS) resulting from the numerical simulation of pulsating hemodynamic flows in semicoronal domains are analyzed, in the case of both regular semicoronal domains and semicoronal domains with bumpy insertions, mimicking aneurysm-like geometries. A new family of cardiovascular risk indicators, which we name three-band diagrams (TBDs), are introduced, as a sensible generalization of the two standard indicators, i.e., the time-averaged WSS and the oscillatory shear index. TBDs provide a handy access to additional information contained in the dynamic structure of the WSS signal as a function of the physiological risk threshold, thereby allowing a quick visual assessment of the risk sensitivity to individual fluctuations of the physiological risk thresholds. Due to its generality, TBD analysis is expected to prove useful for a wide host of applications in science, engineering, and medicine, where risk assessment plays a central role.
The effects of mid-range repulsion in Lattice Boltzmann models on the coalescence/breakup behavio... more The effects of mid-range repulsion in Lattice Boltzmann models on the coalescence/breakup behaviour of single-component, non-ideal fluids are investigated. It is found that mid-range repulsive interactions allow the formation of spray-like, multi-droplet configurations, with droplet size directly related to the strength of the repulsive interaction. The simulations show that just a tiny ten-percent of mid-range repulsive pseudo-energy can boost the surface/volume ratio of the phaseseparated fluid by nearly two orders of magnitude. Drawing upon a formal analogy with magnetic Ising systems, a pseudo-potential energy is defined, which is found to behave like a quasi-conserved quantity for most of the time-evolution. This offers a useful quantitative indicator of the stability of the various configurations, thus helping the task of their interpretation and classification. The present approach appears to be a promising tool for the computational modelling of complex flow phenomena, such as atomization, spray formation and micro-emulsions, break-up phenomena and possibly glassy-like systems as well.
Taking advantage of a closed-form generalized Maxwell distribution function ͓P. Asinari and I. V.... more Taking advantage of a closed-form generalized Maxwell distribution function ͓P. Asinari and I. V. Karlin, Phys. Rev. E 79, 036703 ͑2009͔͒ and splitting the relaxation to the equilibrium in two steps, an entropic quasiequilibrium ͑EQE͒ kinetic model is proposed for the simulation of low Mach number flows, which enjoys both the H theorem and a free-tunable parameter for controlling the bulk viscosity in such a way as to enhance numerical stability in the incompressible flow limit. Moreover, the proposed model admits a simplification based on a proper expansion in the low Mach number limit ͑LQE model͒. The lattice Boltzmann implementation of both the EQE and LQE is as simple as that of the standard lattice Bhatnagar-Gross-Krook ͑LBGK͒ method, and practical details are reported. Extensive numerical testing with the lid driven cavity flow in two dimensions is presented in order to verify the enhancement of the stability region. The proposed models achieve the same accuracy as the LBGK method with much rougher meshes, leading to an effective computational speed-up of almost three times for EQE and of more than four times for the LQE. Three-dimensional extension of EQE and LQE is also discussed.
Uploads
Papers by Sauro Succi