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    Modelization of heat transfer and fluid dynamics in solar power towers  Open access

     Chiva Segura, Jorge; Lehmkuhl Barba, Oriol; Soria Guerrero, Manel; Oliva Llena, Asensio
    ISES Solar World Congress
    Presentation's date: 2011-08-28
    Presentation of work at congresses

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  • Numerical simulation of turbulence at lower costs: regularization modeling

     Trias Miquel, Francesc Xavier; Gorobets, Andrey; Soria Guerrero, Manel; Oliva Llena, Asensio
    International Conference on Parallel Computational Fluid Dynamics
    Presentation's date: 2011-05-07
    Presentation of work at congresses

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  • Hybrid MPI+OpenMP parallelization of a Navier-Stokes solver for large-scale DNS

     Gorobets, Andrey; Trias Miquel, Francesc Xavier; Borrell Pol, Ricard; Soria Guerrero, Manel; Oliva Llena, Asensio
    International Conference on Computational Heat and Mass Transfer
    Presentation's date: 2011-07-07
    Presentation of work at congresses

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    This work presents a parallel Navier-Stokes solver for the large-scale direct numerical simulation (DNS) of incompressible flows with one periodic direction. It is based on a scalable Poisson solver that combines an FFT diagonalization with a preconditioned conjugate gradient (PCG) method and a direct Schurcomplement based method. Modern architectures of supercomputers with multi-core nodes motivate the use of a two-level hybrid MPI+OpenMP parallelization. The use of the more complex two-level approach has allowed to significantly extend the number of CPUs the solver can efficiently use. Here, the solver has been successfully tested on up to 12800 CPU cores for meshes with up to 109 grid points. However, estimations based on presented results show that more than 50000 CPU cores can potentially be exploited.

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    Hybrid MPI+OpenMP parallelization of an FFT-based 3D Poisson solver that can reach 100000 CPU cores  Open access

     Gorobets, Andrey; Trias Miquel, Francesc Xavier; Borrell Pol, Ricard; Soria Guerrero, Manel; Oliva Llena, Asensio
    International Conference on Parallel Computational Fluid Dynamics
    Presentation's date: 2011-05-07
    Presentation of work at congresses

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    This work is devoted to the development of efficient parallel algorithms for the direct numerical simulation (DNS) of incompressible flows on modern supercomputers. A Poisson solver for problems with one uniform periodic direction is presented here. It is extended with a two-level hybrid MPI+OpenMP parallelization. Advantages and implementation details for the additional OpenMP parallelization are presented and discussed. This upgrade has allowed to significantly extend the range of efficient scalability. Here, the solver has been tested up to 12800 CPU cores for meshes with up to 10 9 nodes. However, estimations based on the presented results show that this range can be potentially stretched beyond 10 5 cores.

    Postprint (author’s final draft)

  • Q-00005

     Oliva Llena, Asensio; Perez Segarra, Carlos David; Castro Gonzalez, Jesus; Rodriguez Pérez, Ivette Maria; Oliet Casasayas, Carles; Lehmkuhl Barba, Oriol; Soria Guerrero, Manel; Torrades Carné, Francesc; Codina Macià, Esteban; Khamashta Shahin, Munir; Rigola Serrano, Joaquim
    Participation in a competitive project

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  • Large Eddy Simulation of airflow in a single family house

     Mohan Damle, Rashmin; Colomer Rey, Guillem; Soria Guerrero, Manel; Lehmkuhl Barba, Oriol; Oliva Llena, Asensio
    International High Performance Buildings Conference
    Presentation's date: 2010-07-14
    Presentation of work at congresses

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    This work is addressed to contribute to the progress in the determination of indoor air flow in buildings. The air flow in such environments is caused by natural convection, stack and wind effects, infiltration of ambient air and mechanical ventilation. It is important to be able to predict the pressure, temperature and velocity distributions in order to maintain an adequate indoor environment and to minimize the energy demand at the same time. The problem is difficult due to the large and complex geometry involved, the changing boundary conditions, the mixture of free and forced convection and especially, because the flows are turbulent. The purpose of this work is to explore the feasibility of the use of Large Eddy Simulation (LES) models to carry out full scale simulations of airflow in buildings. A review of the previous works shows that the use of LES for this kind of problems has been restricted to idealized geometries and relatively low Re numbers. In this work, for code validation, a 3D cavity with mixed convection is simulated and the numerical results are compared with the experimental data of Blay, et al. (1992). Then, a single family house with a realistic geometry, Re number of 11834 and Rayleigh number of 2.4 x 1010 is solved using a Yoshizawa Smagorinsky LES model. The code TermoFluids has been used for the simulation and post-processing of the results.

  • Direct numerical simulation of a differentially heated cavity of aspect ratio 4 with Rayleigh numbers up to 10(11) - Part I: Numerical methods and time-averaged flow

     Trias Miquel, Francesc Xavier; Gorobets, Andrey; Soria Guerrero, Manel; Oliva Llena, Asensio
    International journal of heat and mass transfer
    Date of publication: 2010-01-31
    Journal article

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    A set of direct numerical simulations of a differentially heated cavity of aspect ratio 4 with adiabatic horizontal walls is presented. The five configurations selected here (Rayleigh numbers based on the cavity height View the MathML source and View the MathML source) cover a relatively wide range of Ra from weak to fully developed turbulence. A short overview of the numerical methods and the methodology used to verify the code and the simulations is presented. The time-averaged flow results are presented and discussed in this first part. Significant changes are observed for the two highest Ra for which the transition point at the boundary layers clearly moves upstream. Such displacement increases the top and bottom regions of disorganisation shrinking the area in the cavity core where the flow is stratified. Consequently, thermal stratification values are significantly greater than unity (1.25 and 1.41, respectively).

  • A scalable parallel Poisson solver for three-dimensional problems with one periodic direction

     Gorobets, Andrey; Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Oliva Llena, Asensio
    Computers and fluids
    Date of publication: 2010-03
    Journal article

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  • Direct numerical simulation of a differentially heated cavity of aspect ratio 4 with Rayleigh numbers up to 10(11) - Part II: Heat transfer and flow dynamics

     Trias Miquel, Francesc Xavier; Gorobets, Andrey; Soria Guerrero, Manel; Oliva Llena, Asensio
    International journal of heat and mass transfer
    Date of publication: 2010-01-31
    Journal article

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    This is the second of a two-part paper on five direct numerical simulations of a differentially heated cavity of aspect ratio 4 with adiabatic horizontal walls (Rayleigh numbers based on the cavity height. The numerical methods and the time-averaged flow results were presented in the Part I. The heat transfer and the flow dynamics, including the turbulent statistics, the global kinetic energy balances and the internal waves motion phenomenon, are herewith described and discussed. The power-law scalings of the total kinetic dissipation rate and the Nusselt number suggest that a state of transition to a new scaling regime has been reached for the highest Ra.

  • From extruded-2D to fully-3D geometries for DNS: a multigrid-based extension of the Poisson solver

     Gorobets, Andrey; Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Perez Segarra, Carlos David; Oliva Llena, Asensio
    Lecture notes in computational science and engineering
    Date of publication: 2010
    Journal article

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    Direct numerical simulation (DNS) of incompressible flows is an essential tool for improving the understanding of the physics of turbulence and for the development of better turbulence models. The Poisson equation, the main bottleneck from a parallel point of view, usually also limits its applicability for complex geometries. In this context, efficient and scalable Poisson solvers on fully-3D geometries are of high interest.In our previous work, a scalable algorithm for Poisson equation was proposed. It performed well on both small clusters with poor network performance and supercomputers using efficiently up to a thousand of CPUs. This algorithm named Krylov-Schur-Fourier Decomposition (KSFD) can be used for problems in parallelepipedic 3D domains with structured meshes and obstacles can be placed inside the flow. However, since a FFT decomposition is applied in one direction, mesh is restricted to be uniform and obstacles to be 2D shapes extruded along this direction.The present work is devoted to extend the previous KSFD algorithm to eliminate these limitations. The extension is based on a two-level Multigrid (MG) method that uses KSFD as a solver for second level. The algorithm is applied for a DNS of a turbulent flow in a channel with wall-mounted cube. Illustrative results at Re t = 590 (based on the cube height and the bulk velocity Re h = 7235) are shown.

  • Modelización y resolución numérica de un sistema de acumulación de calor sensible sólido-líquido

     Rodriguez Pérez, Ivette Maria; Oliva Llena, Asensio; Soria Guerrero, Manel
    Date: 2010-02-05
    Report

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  • DESARROLLO NUEVOS ALGORITMOS PARA LA APLICACION DE TECNICAS LES A LA SIMULACION DEL COMPORTAMIENTO TERMICO Y FLUIDO-DINAMICO

     Kizildag, Deniz; Lehmkuhl Barba, Oriol; Oliva Llena, Asensio; Soria Guerrero, Manel
    Participation in a competitive project

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  • Parameter-free symmetry-preserving regularization modeling of a turbulent differentially heated cavity

     Trias Miquel, Francesc Xavier; Verstappen, R.W.C.P.; Gorobets, Andrey; Soria Guerrero, Manel; Oliva Llena, Asensio
    Computers and fluids
    Date of publication: 2010-06-23
    Journal article

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    Since direct numerical simulations of buoyancy driven flows cannot be computed at high Rayleigh numbers, a dynamically less complex mathematical formulation is sought. In the quest for such a formulation, we consider regularizations (smooth approximations) of the non-linearity: the convective term is altered to reduce the production of small scales of motion by means of vortex stretching. In doing so, we propose to preserve the symmetry and conservation properties of the convective terms exactly. This requirement yielded a novel class of regularizations [Comput Fluids 2008;37:887] that restrain the convective production of smaller and smaller scales of motion in an unconditionally stable manner, meaning that the velocity cannot blow up in the energy-norm (in 2D also: enstrophy-norm). The numerical algorithm used to solve the governing equations preserves the symmetry and conservation properties too. In the present work, a criterion to determine dynamically the regularization parameter (local filter length) is proposed: it is based on the requirement that the vortex stretching must stop at the scale set by the grid. Therefore, the proposed method constitutes a parameter-free turbulence model. The resulting regularization method is tested for a 3D natural convection flow in an air-filled (Pr = 0.71) differentially heated cavity of height aspect ratio 4. Direct comparison with DNS results at Rayleigh number 6.4 X 10 8 ≤ Ra ≤ 10 11 shows fairly good agreement even for very coarse grids. Finally, the robustness of the method is tested by performing simulations with Ra up to 10 17. A 2/7 scaling law of Nusselt number has been obtained for the investigated range of Ra.

  • Modular Simulation of Thermal Systems.

     Mohan Damle, Rashmin
    Defense's date: 2009-06-18
    Department of Heat Engines, Universitat Politècnica de Catalunya
    Theses

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    Parameter-free symmetry-preserving regularization modelling of turbulent natural convection flows  Open access

     Trias Miquel, Francesc Xavier; Verstappen, R.W.C.P.; Soria Guerrero, Manel; Oliva Llena, Asensio
    Conference on Turbulence and Interactions
    Presentation's date: 2009-06
    Presentation of work at congresses

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    Since direct numerical simulations of natural convection flows cannot be performed at high Ra-numbers, a dynamically less complex mathematical formulation is sought. In the quest for such a formulation, we consider regularizations (smooth approximations) of the nonlinearity. The regularization method basically alters the convective terms to reduce the production of small scales of motion by means of vortex stretching. In doing so, we propose to preserve the symmetry and conservation properties of the convective terms exactly. This requirement yields a novel class of regularizations that restrain the convective production of smaller and smaller scales of motion by means of vortex stretching in an unconditional stable manner, meaning that the velocity cannot blow up in the energy-norm (in 2D also: enstrophy-norm). The numerical algorithm used to solve the governing equations preserves the symmetry and conservation properties too. The regularization model is successfully tested for a 3D natural convection flow in air-filled (Pr = 0.71) differentially heated cavity of height aspect ratio 4 at Ra = 10 10 and 10 11. Moreover, a method to dynamically determine the regularization parameter (local filter length) is also proposed and tested.

    Postprint (author’s final draft)

  • DNS of turbulent natural convection flows on the MareNostrum supercomputer

     Trias Miquel, Francesc Xavier; Gorobets, Andrey; Soria Guerrero, Manel; Oliva Llena, Asensio
    Lecture notes in computational science and engineering
    Date of publication: 2009
    Journal article

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    A code for the direct numerical simulation (DNS) of incompressible turbulent flows that provides a fairly good scalability for a wide range of computer architectures has been developed. The spatial discretization of the incompressible Navier-Stokes equations is carried out using a fourth-order symmetry-preserving discretization. Since the code is fully explicit, from a parallel point of view, the main bottleneck is the Poisson equation. In the previous version of the code, that was conceived for low cost PC clusters with poor network performance, a Direct Schur-Fourier Decomposition (DSFD) algorithm was used to solve the Poisson equation. Such method, that was very efficient for PC clusters, can not be efficiently used with an arbitrarily large number of processors, mainly due to the RAM requirements (that grows with the number of processors). To do so, a new version of the solver, named Krylov-Schur-Fourier Decomposition (KSFD), is presented here. Basically, it is based on the Direct Schur Decomposition (DSD) algorithm that is used as a preconditioner for a Krylov method (CG) after Fourier decomposition. Benchmark results illustrating the robustness and scalability of the method on the MareNostrum supercomputer are presented and discussed. Finally, illustrative DNS simulations of wall-bounded turbulent flows are also presented.

  • CENTRE TECNOLOGIC TRANSFERENCIA CALOR

     Rigola Serrano, Joaquim; Castro Gonzalez, Jesus; Rodriguez Pérez, Ivette Maria; Oliet Casasayas, Carles; Borrell Pol, Ricard; Carmona Muñoz, Angel; Torras Ortiz, Santiago; Mohan Damle, Rashmin; Lopez Mas, Joan; Kizildag, Deniz; Ablanque Mejia, Nicolas; Lehmkuhl Barba, Oriol; Soria Guerrero, Manel; Gorobets, Andrey; Capdevila Paramio, Roser; Jaramillo Ibarra, Julian Ernesto; Morales Ruiz, Sergio; Trias Miquel, Francesc Xavier; Perez Segarra, Carlos David; Sadurni Caballol, Alexandre; Oliva Llena, Asensio
    Participation in a competitive project

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  • Parameter-free modelling of a turbulent differentially heated cavity with Rayleigh number up to 10e11

     Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Gorobets, Andrey; Verstappen, R.W.C.P.
    International Symposium on Turbulence, Heat and Mass Transfer
    Presentation's date: 2009-09-16
    Presentation of work at congresses

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    Since direct numerical simulations of natural convection in a differentially heated cavity cannot be performed at high Rayleigh numbers, a dynamically less complex mathematical formulation is sought. In the quest for such a formulation, we consider regularizations (smooth approximations) of the nonlinearity. The regularization method basically alters the convective terms to reduce the production of small scales of motion by means of vortex stretching. In doing so, we propose to preserve the symmetry and conservation properties of the convective terms exactly. This requirement yielded a novel class of regularizations that restrain the convective production of smaller and smaller scales of motion by means of vortex stretching in an unconditional stable manner, meaning that the velocity cannot blow up in the energy-norm (in 2D also: enstrophy-norm). The numerical algorithm used to solve the governing equations preserves the symmetry and conservation properties too. In the present work we propose to determine the filter length dynamically with the requirement that the vortex stretching must be stopped at the scale set by the grid. Finally, the proposed parameter-free regularization model is successfully tested for a turbulent natural convection flow in an air-filled differentially heated cavity of aspect ratio 4 with Rayleigh number up to 10 11.

  • Turbulent flow around a wall-mounted cube: direct numerical simulation and regularization modelling.

     Trias Miquel, Francesc Xavier; Gorobets, Andrey; Verstappen, R.W.C.P.; Soria Guerrero, Manel; Oliva Llena, Asensio
    International Conference on Parallel Computational Fluid Dynamics
    Presentation's date: 2009-05-01
    Presentation of work at congresses

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  • Numerical study of natural convection heat transfer from an isothermal thin plate.

     Jaramillo Ibarra, Julian Ernesto; Oliva Llena, Asensio; Perez Segarra, Carlos David; Soria Guerrero, Manel
    International Symposium on Turbulence, Heat and Mass Transfer
    Presentation's date: 2009-09-16
    Presentation of work at congresses

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    In this work detailed numerical simulations of natural convection heat transfer around an isothermal thin plate with different inclinations are carried out. The numerical approach is based on the finite volume technique for the study of air movement around the plate and its surroundings using symmetry-preserving formulation. To solve turbulence, Direct Numerical Simulation (DNS) or Large Eddy Simulation (LES) are selected. After verification of the numerical solutions and comparison of the results from different turbulence models, a data reduction of the numerical results is carried out in order to determine local and global heat transfer coefficients. Furthermore, the influence of Rayleigh number and plate inclination on flow characteristics and heat transfer coefficients is investigated.

  • Turbulent natural convection in an open cavity: a numerical study

     Chiva Segura, Jorge; Soria Guerrero, Manel; Oliva Llena, Asensio; Lehmkuhl Barba, Oriol
    International Symposium on Turbulence, Heat and Mass Transfer
    Presentation's date: 2009-09-16
    Presentation of work at congresses

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    In this paper three-dimensional turbulent natural convection heat transfer in a simplified solar receiver open cavity is studied. Smagorinsky-LES (Large Eddy Simulation) model is chosen for turbulence flow computation. The validity of the Boussinesq approximation for this problem is discused due to large difference of temperatures between the air and the receiver. Rayleigh numbers up to 10^13 are considered in this work.

  • Parallel algorithms for direct numerical simulations of incompressible turbulent flows on supercomputers

     Gorobets, Andrey
    Defense's date: 2008-10-17
    Department of Heat Engines, Universitat Politècnica de Catalunya
    Theses

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  • DNS of an air-filled differentially heated cavity of aspect ratio 4 at ra-numbers 6.4x10, 2x10, 1x10, 3x10 and 10

     Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Gorobets, Andrey; Oliva Llena, Asensio
    Fifth European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS)
    Presentation of work at congresses

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  • Paralllel direct Poisson solver for DNS of complex turbulent flows using Unstructured Meshes

     Borrell Pol, Ricard; Lehmkuhl Barba, Oriol; Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Oliva Llena, Asensio
    2008 Parallel Computational Fluid Dynamics Conference
    Presentation of work at congresses

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  • Parallel Schur-Forrier decomposition for the efficient solution of poisson equation on massive extruded unstructured meshes

     Borrell Pol, Ricard; Lehmkuhl Barba, Oriol; Soria Guerrero, Manel; COLOMER, G
    Fifth European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS)
    Presentation of work at congresses

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  • From extruded-2D to fully-3D geometries for DNS: a Multigrid-based extension of the Poisson solver

     Gorobets, Andrey; Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Perez Segarra, Carlos David; Oliva Llena, Asensio
    2008 Parallel Computational Fluid Dynamics Conference
    Presentation of work at congresses

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  • Direct numerical simulations of two- and three-dimensional turbulent natural convection flows in a differentially heated cavity of aspect ratio 4

     Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Oliva Llena, Asensio; Perez Segarra, Carlos David
    Journal of fluid mechanics
    Date of publication: 2007-09
    Journal article

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  • TERMOFLUIDS: A new Parallel unstructured CFD code for the simulation of turbulent industrial problems on low cost PC Cluster

     Lehmkuhl Barba, Oriol; Perez Segarra, Carlos David; Borrell Pol, Ricard; Soria Guerrero, Manel; Oliva Llena, Asensio
    2007 Parallel Computational Fluid Dynamics Conference
    Presentation of work at congresses

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  • DNS of Turbulent Natural Convection Flows on the MareNostrum supercomputer

     Soria Guerrero, Manel
    2007 Parallel Computational Fluid Dynamics Conference
    Presentation's date: 2007-05-21
    Presentation of work at congresses

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  • Schur complement methods for the solution of Poisson equation with unstructured meshes

     Borrell Pol, Ricard; Lehmkuhl Barba, Oriol; Soria Guerrero, Manel; Oliva Llena, Asensio
    2007 Parallel Computational Fluid Dynamics Conference
    Presentation of work at congresses

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  • DNS of Turbulent Natural Convection Flows on the MareNostrum supercomputer

     Trias Miquel, Francesc Xavier; Gorobets, Andrey; Soria Guerrero, Manel; Oliva Llena, Asensio
    2007 Parallel Computational Fluid Dynamics Conference
    Presentation of work at congresses

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  • Analysis of different numerical schemes for the resolution of convection - diffussion equations using finite volume methods on three dimensional unstructured grids. Part II: Numerical Analysis

     Perez Segarra, Carlos David; Soria Guerrero, Manel; Oliva Llena, Asensio
    Numerical heat transfer. Part B, fundamentals
    Date of publication: 2006-10
    Journal article

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  • A Direct Schur-Fourier Decomposition for the Efficient Solution of High-Order Poisson Equations on Loosely Coupled Parallel Computers

     Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Perez Segarra, Carlos David; Oliva Llena, Asensio
    Numerical linear algebra with applications
    Date of publication: 2006-05
    Journal article

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  • Direct numerical simulation and regularization modelling of turbulent flows on loosely coupled parallel computers using symmnetry-preserving discretizations

     Trias Miquel, Francesc Xavier
    Defense's date: 2006-12-19
    Department of Heat Engines, Universitat Politècnica de Catalunya
    Theses

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  • Heat transfer and fluid-dynamics in double and single skin facades  Open access

     Faggembauu de Raush, Debora Fabiana
    Defense's date: 2006-12-19
    Department of Heat Engines, Universitat Politècnica de Catalunya
    Theses

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    Una proporción muy importante del presupuesto energético total de los países europeos es destinado al consumo energético del sector de la edificación, tanto en el ámbito doméstico como terciario. Debido a que esta tendencia continúa en aumento, es de vital importancia optimizar los edificios tanto desde el punto de vista de las envolventes térmicas, como de las instalaciones térmicas y las condiciones de operación y funcionamiento.Esta tesis incide fundamentalmente en el diseño eficiente de la fachada, ya que éste es uno de los principales elementos que determinan el comportamiento térmico de los edificios. No sólo actúa como barrera entre las condiciones externas e internas, sino que el diseño eficiente de la misma, contribuye en forma relevante a la reducción del consumo de calefacción, aire acondicionado, ventilación e iluminación. Asimismo, es un elemento que incide notablemente en las condiciones de salubridad y confort. Actualmente, existe un gran auge del uso de fachadas completamente hechas de vidrio, este tipo de construcción presenta una serie de ventajas arquitectónicas y estéticas, pero desde el punto de vista térmico pueden representar problemas de sobrecalentamientos y pérdidas de energía importantes, tanto en las áreas mediterráneas como en otras zonas climáticas. En este sentido, las fachadas de doble piel, compuestas por dos capas separadas por un canal de aire, usado para evacuar o aprovechar la energía solar absorbida por la fachada, pueden representar una opción de diseño válida para solventar esta problemática. Asimismo, este tipo de diseño puede producir unas condiciones de confortabilidad adecuadas debido a la reducción de las temperaturas de las superficies interiores de las fachadas.El objetivo de esta tesis es el de contribuir al estudio de sistemas pasivos en general, y fachadas avanzadas en particular. Para ello, se ha desarrollado una herramienta numérica para la simulación de fachadas de edificios de simple y doble piel. La principal característica de este código es la de asumir un comportamiento unidimensional y transitorio. Las ecuaciones gobernantes (continuidad, momentum y conservación de la energía) son resueltas mediante la aplicación del método de volúmenes finitos. Las fachadas incluyen elementos arquitectónicos novedosos, como materiales de cambio de fase, aislamiento transparente, superficies selectivas y colectores solares con acumuladores integrados en la superficie de las fachadas. En la tesis, se describen las características de los modelos físicos y matemáticos implementados y se definen parámetros instantáneos e integrados que describen el comportamiento térmico de las fachadas. Los modelos numéricos implementados han sido sujetos a procesos de verificación y validación en diferentes formas: i) por comparación de los resultados numéricos con los obtenidos para situaciones simplificadas que cuentan con solución analítica, ii) por comparación con parámetros globales tabulados en la literatura de ciertas configuraciones de fachadas, y iii) por comparación de los resultados numéricos con los obtenidos experimentalmente en celdas de ensayo sometidas a diferentes condiciones climáticas.Se presentan resultados de estudios paramétricos de diferentes configuraciones de fachadas y aplicaciones del código numérico para la optimización del diseño de fachadas de edificios emblemáticos del entorno. Como acciones futuras, se prevé la conexión de este tipo de simulaciones con otras de más alto nivel, bidimensionales, para optimizar zonas concretas de las fachadas.

    A significant proportion of the total national energy budget of european countries goes toward energy consumption in buildings, therefore the efforts addressed to optimize building's thermal behaviour are of vital importance. In this sense, facades play a fundamental role. Not only do they act as barriers between external and internal conditions, but they can also help to reduce the consumption of energy for heating, ventilation and air conditioning. Moreover, they can help to produce healthy and comfortable indoor conditions. The use of large, transparent areas in facades is a common current practice. Despite the architectural interest of these glazed areas, in Mediterranean climatic conditions they are responsible for building overheating. In these zones, double-skin envelopes made up of two layers of glass separated by an air channel -to collect or evacuate the solar energy absorbed by the facade- are considered to be a design option that could resolve this issue. In other climatic conditions, large heat losses may constitute the most determinant factor. Anyway, the comfort parameters are influenced by the large transparent areas, also in this design aspect, double skin facades may contribute to obtain more comfortable and pleasant living spaces.The objectives of this thesis are to give a step forward in the study and numerical analysis of passive systems in general, and advanced facades in particular. A one-dimensional and transient numerical code for the simulation of double and single skin facades including advanced technological elements, like phase change materials, transparent insulation and facade integrated collectors-accumulators has been developed. The features of the physic and mathematical models implemented are described and instantaneous or integratedperformance parameters describing thermal behaviour of the facades are defined. The numerical models implemented within the numerical tool have been subjected to a verification and validation process in different forms: by comparing the numerical results with those obtained for simplified situations with analytical solutions, with tabulated global performance coefficients of simple façade configurations and with the results of other building simulation codes. Experimental research has been carried out in test cells situated at different geographical locations, thus they were subjected to different climatic conditions. The main objective of the developed numerical code is to simulate advanced facades in order to assess the long term performance, and to account with a virtual tool to test passive designs, including challenging innovations.The applications of the numerical tool described in this thesis, for the optimisation of facades of real buildings are presented. As future actions, the link of the one-dimensional simulations produced by this numerical tool with a multi-dimensional simulation of specific zones of the facades is foreseen.

  • Analysis of transient effects on the performance of advanced double and single skin facades including transparent insulation. Numerical study and experimental validation

     Faggembauu de Raush, Debora Fabiana; Oliva Llena, Asensio; Soria Guerrero, Manel
    International Conference on Solar Heating, Cooling and Buildings
    Presentation of work at congresses

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  • Regularization models for the simulation of turbulence in a differentially heated cavity

     Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Oliva Llena, Asensio; Verstappen, R.W.C.P.
    European Computational Fluid Dynamics Conference (ECCOMAS CFD 2006)
    Presentation of work at congresses

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  • Direct Numerical Simulations of Turbulent Natural Convection in a Differentially Heated Cavity of Aspect Ratio 4 at Rayleigh numbers 6.4e8, 2e9 and 1e10

     Trias Miquel, Francesc Xavier; Lehmkuhl Barba, Oriol; Soria Guerrero, Manel; Oliva Llena, Asensio
    International Symposium on Turbulence, Heat and Mass Transfer
    Presentation of work at congresses

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  • Detailed thermodynamic characterization of hermetic reciprocating compressors

     Perez Segarra, Carlos David; Rigola Serrano, Joaquim; Soria Guerrero, Manel; Oliva Llena, Asensio
    International journal of refrigeration / Revue internationale du froid
    Date of publication: 2005-06
    Journal article

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  • Direct numerical simulation of turbulent flows on a low cost PC cluster

     Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Perez Segarra, Carlos David; Oliva Llena, Asensio
    2005 Parallel Computational Fluid Dynamics Conference
    Presentation of work at congresses

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  • Direct numerical simulation of a three-dimensional natural convection flow in a differentially heated cavity of aspect ratio 4

     Soria Guerrero, Manel; Trias Miquel, Francesc Xavier; Perez Segarra, Carlos David; Oliva Llena, Asensio
    Numerical heat transfer. Part A, applications
    Date of publication: 2004-06
    Journal article

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  • Advanced solar facades with integrated collector-accumulators for domestic hot water and space heating applications

     Faggembauu de Raush, Debora Fabiana; Soria Guerrero, Manel; Oliva Llena, Asensio; Cadafalch Rabasa, Jordi
    International Conference on Solar Heating, Cooling and Buildings
    Presentation of work at congresses

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  • Direct Numerical Simulation of Turbulent Natural Convection Flows on PC Clusters Using a Fourth-Order Symmetry-Preserving Method

     Soria Guerrero, Manel; Trias Miquel, Francesc Xavier; Perez Segarra, Carlos David; Oliva Llena, Asensio
    2004 Parallel Computational Fluid Dynamics Conference
    Presentation of work at congresses

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  • An Efficient Direct Algorithm for the Solution of the Fourth-Order Poisson Equation on Loosely Coupled Parallel Computers

     Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Perez Segarra, Carlos David; Oliva Llena, Asensio
    2004 Parallel Computational Fluid Dynamics Conference
    Presentation of work at congresses

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  • DNS of 3D Turbulent Natural Convection Flows Using Low Cost Parallel Computers, AIAA Paper 2004-595

     Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Perez Segarra, Carlos David; Oliva Llena, Asensio
    42nd AIAA Aerospace Sciences Meeting and Exhibit
    Presentation of work at congresses

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  • GREENFACADE project: Task 8. Numerical code validation

     Soria Guerrero, Manel; Oliva Llena, Asensio
    Date: 2004-12
    Report

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  • GREENFACADE project: Task 10. Plan of maintenance

     Soria Guerrero, Manel; Oliva Llena, Asensio
    Date: 2004-12
    Report

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  • GREENFACADE project: Task 11. Conclusions

     Soria Guerrero, Manel; Oliva Llena, Asensio
    Date: 2004-12
    Report

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  • GREENFACADE project: Task 9. Arcbitectural integration and training

     Soria Guerrero, Manel; Oliva Llena, Asensio
    Date: 2004-12
    Report

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