A massively parallel fractional step solver for incompressible flows

Houzeaux, Guillaume; Vázquez, Mariano; Aubry, Romain; María, José

doi:10.1016/j.jcp.2009.05.019

Cited by 86 publications

(71 citation statements)

References 39 publications

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“…All the details on the parallelisation of Alya can be found in papers such as [15,11,19]. We give here the general idea of the MasterWorker strategy.…”

Section: Master-worker Strategymentioning

confidence: 99%

“…The momentum and continuity equations are solved with unsymmetric and symmetric iterative solvers respectively. For the momentum equations, the GMRES is considered to be the best choice while the Conjugate Gradient (CG) or Deflated CG are the choices for the continuity equation [19,15]. The GMRES solver is also used to solve the enthalpy transport and the species mass fractions.…”

Section: The Kiln Furnace -Implicit Incompressible Navier-stokes Chementioning

confidence: 99%

“…Alya general view. Alya (see for instance [30,15,12,5,17]) is a simulation code developed at Barcelona Supercomputing Center (BSC-CNS) since 2004, whose main architects are authors GH and MV. Alya is not a born-sequential simulation code which was parallelized afterwards.…”

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confidence: 99%

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Alya: Multiphysics engineering simulation toward exascale

Vázquez

Houzeaux

Korić

et al. 2016

Journal of Computational Science

186

111

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Abstract. Alya is a multi-physics simulation code developed at Barcelona Supercomputing Center (BSC). From its inception Alya code is designed using advanced High Performance Computing programming techniques to solve coupled problems on supercomputers efficiently. The target domain is engineering, with all its particular features: complex geometries and unstructured meshes, coupled multi-physics with exotic coupling schemes and physical models, ill-posed problems, flexibility needs for rapidly including new models, etc. Since its beginnings in 2004, Alya has scaled well in an increasing number of processors when solving single-physics problems such as fluid mechanics, solid mechanics, acoustics, etc. Over time, we have made a concerted effort to maintain and even improve scalability for multi-physics problems. This poses challenges on multiple fronts, including: numerical models, parallel implementation, physical coupling models, algorithms and solution schemes, meshing process, etc. In this paper, we introduce Alya's main features and focus particularly on its solvers. We present Alya's performance up to 100.000 processors in Blue Waters, the NCSA supercomputer with selected multi-physics tests that are representative of the engineering world. The tests are incompressible flow in a human respiratory system, low Mach combustion problem in a kiln furnace, and coupled electro-mechanical contraction of the heart. We show scalability plots for all cases and discuss all aspects of such simulations, including solver convergence.Key words. Multi-physics coupling, Parallelisation, Computational Mechanics 1. Introduction. Across a range of engineering fields, the use of computational models is pervasive in the whole design and manufacturing process. In complex systems, High Performance Computing (HPC) plays an essential role in simulation and modelling. Researchers and manufacturing teams depend on HPC to create safe cars and energy-efficient aircraft as well as effective communication systems and efficient supply chain models. Availability of advanced HPC technologies has also fundamentally altered the investigative paradigm in the field of biomechanics. But paradoxically, for many engineers and researchers, the existing hardware and software cannot be used to solve their problems. There are many reasons why this happens, but we focus here in only two. On one hand, current HPC systems lack the computational power, network bandwidth and data storage needed for solving tomorrow's real-world engineering challenges. On the other hand, while emerging peta-scale computing is already a strategic enabler of large-scale simulations in many scientific areas (such as astronomy, biology and chemistry), even the most powerful hardware will fail to deliver on its full potential unless matched with simulation software designed specifically for such environments.Several papers describe the effort of performing large-scale simulations on supercomputers, covering key areas: molecular dynamics [26], mantle convection in solid earth dynami...

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“…All the details on the parallelisation of Alya can be found in papers such as [15,11,19]. We give here the general idea of the MasterWorker strategy.…”

Section: Master-worker Strategymentioning

confidence: 99%

Section: The Kiln Furnace -Implicit Incompressible Navier-stokes Chementioning

confidence: 99%

See 1 more Smart Citation

Alya: Multiphysics engineering simulation toward exascale

Vázquez

Houzeaux

Korić

et al. 2016

Journal of Computational Science

186

111

View full text Add to dashboard Cite

show abstract

“…Houzeaux et al, 2009;Vázquez et al, 2016) is a high performance computing (HPC) multi-physics parallel solver based on a finite element method able to run with thousands of processors with an optimal scalability. Within this multi-physics general framework, Avila et al (2013) implemented a solver for the atmospheric boundary layer based on the RANS equations and a κ − turbulence model adapted to atmospheric flows in complex terrains.…”

Section: Microscale Wind Modelling Using Alya-cfdwindmentioning

confidence: 99%

“…4. The methodology uses the concept of transfer functions to couple the mesoscale Weather Research and Forecasting (WRF) (Skamarock et al, 2008) model with the CFD code Alya (Houzeaux et al, 2009) adapted to atmospheric boundary layer flows (Avila et al, 2013). Section 5 shows the TWODEE-2.1 model results for the 1986 Lake Nyos case of study and discusses how and why the model new features increase the accuracy of simulations.…”

Section: Introductionmentioning

confidence: 99%

High-resolution modelling of atmospheric dispersion of dense gas using TWODEE-2.1: application to the 1986 Lake Nyos limnic eruption

Folch

Barcons

Kozono

et al. 2017

Nat. Hazards Earth Syst. Sci.

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Abstract. Atmospheric dispersal of a gas denser than air can threat the environment and surrounding communities if the terrain and meteorological conditions favour its accumulation in topographic depressions, thereby reaching toxic concentration levels. Numerical modelling of atmospheric gas dispersion constitutes a useful tool for gas hazard assessment studies, essential for planning risk mitigation actions. In complex terrains, microscale winds and local orographic features can have a strong influence on the gas cloud behaviour, potentially leading to inaccurate results if not captured by coarser-scale modelling. We introduce a methodology for microscale wind field characterisation based on transfer functions that couple a mesoscale numerical weather prediction model with a microscale computational fluid dynamics (CFD) model for the atmospheric boundary layer. The resulting time-dependent high-resolution microscale wind field is used as input for a shallow-layer gas dispersal model (TWODEE-2.1) to simulate the time evolution of CO 2 gas concentration at different heights above the terrain. The strategy is applied to review simulations of the 1986 Lake Nyos event in Cameroon, where a huge CO 2 cloud released by a limnic eruption spread downslopes from the lake, suffocating thousands of people and animals across the Nyos and adjacent secondary valleys. Besides several new features introduced in the new version of the gas dispersal code (TWODEE-2.1), we have also implemented a novel impact criterion based on the percentage of human fatalities depending on CO 2 concentration and exposure time. New model results are quantitatively validated using the reported percentage of fatalities at several locations. The comparison with previous simulations that assumed coarser-scale steady winds and topography illustrates the importance of highresolution modelling in complex terrains.

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Plasmon‐Enhanced Photocatalysis on Anisotropic Gold Nanorod Arrays

et al. 2013

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The field of photocatalysis is an active area owing to the possible contributions to solve some challenging problems such as sustainable energy production, environmental pollution control, and even global warming. Unfortunately, traditional photocatalysts, especially semiconductors, suffer from inherent deficiencies, which include high activation barriers, the low mobility of charge carriers, and poor long‐term stabilities. Herein, we demonstrate a plasmonic photocatalyst based on unidirectional gold nanorod arrays fabricated by using the oblique‐angle deposition (OAD) technique. The fabricated gold nanorod arrays exhibit a remarkable plasmonic anisotropy, which depends on the direction of the incoming light. By employing these arrays as a plasmonic catalyst, a clear improvement and control in the catalytic reduction of o‐nitroaniline to 1,2‐benzenediamine, depending on the directionalities and anisotropic plasmonic properties of the gold nanorods, was obtained. These results suggest that such unique characteristics of directional gold nanorod arrays could greatly impact several technological areas, not only in plasmon‐enhanced photocatalysis but in biosensing and optofluidic applications.

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A massively parallel fractional step solver for incompressible flows

Cited by 86 publications

References 39 publications

Alya: Multiphysics engineering simulation toward exascale

Alya: Multiphysics engineering simulation toward exascale

High-resolution modelling of atmospheric dispersion of dense gas using TWODEE-2.1: application to the 1986 Lake Nyos limnic eruption

Plasmon‐Enhanced Photocatalysis on Anisotropic Gold Nanorod Arrays

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