Documents published in Scipedia

• El método de Level Set: Revisión y nuevas propuestas

  A. Valls, J. García-Espinosa, E. Oñate

  (2004). Research Report, Nº PI254

  
  

  Abstract

  El método Level Set utilizado en un amplio espectro de problemas de distinta índole, como la simulación de interfaces entre fluidos, el tratamiento de imágenes, la combustión,…tiene como principal objetivo la simulación numérica de la evolución de interfaces entre distintas regiones en contacto. El presente estudio es una revisión y aportación de nuevas propuestas para el método Level Set, en particular para su aplicación a la interfaz entre fluidos. Este método formulado independiente del tipo de método utilizado para la integración numérica de las ecuaciones en derivadas parciales que gobiernan el fenómeno a simular, disfruta de gran aceptación en el mundo de las diferencias finitas y existe abundante literatura al respecto. En este estudio se ha considerado la combinación del método Level Set y el método de Elementos Finitos no tan usual como en el caso anterior, dotando a este estudio de cierta singularidad. El estudio se ha organizado en 9 secciones o capítulos. En capítulos del 1 al 5 se presenta una introducción teórica al método Level Set con todo el rigor matemático. Se introducen también las últimas ideas desarrolladas en este campo. A lo largo de estos capítulos se propone a modo de ejemplo la aplicación del método Level Set a la interfaz entre dos fluidos. Los capítulos 6 y 7 se presentan los detalles computacionales de este método, así como los detalles de los algoritmos necesarios para la aplicación del método de Level Set. También se hace una revisión de la discretización por el método de los Elementos Finitos estabilizados de la ecuación de transporte, necesaria para la aplicación del método. Los capítulos 8 y 9 recogen varios resultados y conclusiones de la aplicación de este método a distintos ejemplos en dos y tres dimensiones, algunos de ellos presentes en gran parte de la literatura existente.

  Abstract
  El método Level Set utilizado en un amplio espectro de problemas de distinta índole, como la simulación de interfaces entre fluidos, el tratamiento de [...]

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• Desarrollo del código de elementos finitos TDYN para estudio de la hidrodinámica de barcos. Aplicaciones al diseño de veleros de la Copa América.

  E. Oñate, J. García-Espinosa

  (2004). Research Report, Nº PI246

  
  

  Abstract

  En los últimos años CIMNE ha desarrollado en colaboración con la empresa COMPASS Ingeniería y Sistemas, S.A. (www.compassis.com) un nuevo código de cálculo basado en el método de los elementos finitos para el estudio fluido-dinámico de embarcaciones. El código permite reproducir de forma virtual con fidelidad el denominado “Canal de Ensayos Hidrodinámicos” (CEH) utilizado regularmente para la evaluación experimental de la resistencia hidrodinámica de barcos. El nuevo código, denominado TDYN, es una alternativa a mucho más económica y precisa a los ensayos en el CEH, al permitir analizar el comportamiento de barcos en el agua a escala real, eliminando así los errores de escala usuales en los ensayos experimentales. TDYN incorpora nuevos modelos matemáticos y métodos de elementos finitos avanzados que han llevado a término numerosas publicaciones internacionales. TDYN se desarrolló conjuntamente por investigadores de la Universidad Politécnica de Catalunya (UPC) del Depto. De Resistencia de Materiales y Estructuras de la Escuela Técnica Superior de Ingenieros de Caminos, Canales y Puertos de Barcelona y del Departamento de Ciencia e Ingenieros Náuticas de la Facultad de Náutica de Barcelona en el marco de diversos proyectos europeos y nacionales llevados a término en colaboración con CIMNE y la empresa COMPASS, además de otras empresas de prestigio en el sector naval. TDYN se aplicó al diseño de diversos veleros de la Copa América (en particular por el equipo del barco ALINGHI ganador de la edición de 2003). TDNY lo comercializa actualmente en todo el mundo la empresa COMPASS, una spin-off de la UPC.  

  Abstract
  En los últimos años CIMNE ha desarrollado en colaboración con la empresa COMPASS Ingeniería y Sistemas, S.A. (www.compassis.com) un nuevo código [...]

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• LES turbulence models. Relation with stabilized numerical methods

  A. Valls, J. García-Espinosa, E. Oñate

  (2006). Research Report, Nº PI288

  
  

  Abstract

  One of the aims of this text is to show some important results in LES modelling and to identify which are main mathematical problems for the development of a complete theory. A relevant aspect of LES theory, which we will consider in our work, is the close relationship between the mathematical properties of LES models and the numerical methods used for their implementation. In last years it is more and more common the idea in the scientific community, especially in the numerical community, that turbulence models and stabilization techniques play a very similar role. Methodologies used to simulate turbulent flows, RANS or LES approaches, are based on the same concept: unability to simulate a turbulent flow using a finite discretization in time and space. Turbulence models introduce additional information (impossible to be captured by the approximation technique used in the simulation) to obtain physically coherent solutions. On the other side, numerical methods used for the integration of partial differential equations (PDE) need to be modified in order to able to reproduce solutions that present very high localized gradients. These modifications, known as stabilization techniques, make possible to capture these sharp and localized changes of the solution. According with previous paragraphs, the following natural question appears: Is it possible to reinterpret stabilization methods as turbulence models? This question suggests a possible principle of duality between turbulence modelling and numerical stabilization. More than to share certain properties, actually, it is suggested that the numerical stabilization can be understood as turbulence. The opposite will occur if turbulence models are only necessary due to discretization limitations instead of a need for reproducing the physical behaviour of the flow. Finally: can turbulence models be understood as a component of a general stabilization method?

  Abstract
  One of the aims of this text is to show some important results in LES modelling and to identify which are main mathematical problems for the development of a complete theory. [...]

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• FIC/FEM formulation with matrix stabilizing terms for incompressible floes at low and high Reynolds numbers

  E. Oñate, A. Valls, J. García-Espinosa

  (2006). Research Report, Nº PI282

  
  

  Abstract

  We present a general formulation for incompressible fluid flow analysis using the finite element method. The necessary stabilization for dealing with convective effects and the incompressibility condition are introduced via the Finite Calculus method using a matrix form of the stabilization parameters. This allows to model a wide range of fluid flow problems for low and high Reynolds numbers flows without introducing a turbulence model. Examples of application to the analysis of incompressible flows with moderate and large Reynolds numbers are presented.

  Abstract
  We present a general formulation for incompressible fluid flow analysis using the finite element method. The necessary stabilization for dealing with convective effects and [...]

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• Drag prediction system based on neural networks

  I. Ortigoza, J. García-Espinosa

  (2007). Research Report, Nº PI305

  
  

  Abstract

  In this work we will be based on two experimental-based statistical techniques, which allow us to determine approximately the residual resistance coefficient of the sailboat and the viscous coefficient and wave resistance coefficient in the case of merchants. For the calculation of the residual resistance in sailboats the most used method is the Delft series, and for the calculation of the residual resistance in merchants the most widespread method is that of Holtrop and Mennen. Both methods used experimental data to adjust a function, the results obtained with the functions are quite reliable, but it is difficult to improve the model since the statistical adjustment is complicated. For this reason, in this work we try to overcome that limitation and develop a tool that is capable of performing the same calculations, with the same or better reliability and also that allows to be constantly improved with experimental data. The tool used is the neural network.

  Abstract
  In this work we will be based on two experimental-based statistical techniques, which allow us to determine approximately the residual resistance coefficient of the sailboat [...]

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• Computation of turbulent flows using a finite element formulation

  E. Oñate, A. Valls, J. García-Espinosa

  (2007). Research Report, Nº PI304

  
  

  Abstract

  We present a formulation for analysis of turbulent incompressible flows using a stabilized finite element method (FEM) based on the finite calculus (FIC) procedure. The stabilization terms introduced by the FIC approach allow to solve a wide range of fluid flow problems at different Reynolds numbers, including turbulent flows, without the need of a turbulence model. Examples of application of the FIC/FEM formulation to the analysis of 2D and 3D incompressible flows at large Reynolds numbers exhibiting turbulence features are presented.

  Abstract
  We present a formulation for analysis of turbulent incompressible flows using a stabilized finite element method (FEM) based on the finite calculus (FIC) procedure. The stabilization [...]

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• LES Turbulence models. Relation with stabilized numerical methods

  A. Valls, J. García-Espinosa, E. Oñate

  (2007). Models, Experiments and Computation in Turbulence, R. Castilla, E. Oñate, J. M. Redondo (Eds.), pp. 17-64

  
  

  Abstract

  One of the aims of this text is to show some important results in LES modelling and to identify which are main mathematical problems for the development of a complete theory. A relevant aspect of LES theory, which we will consider in our work, is the close relationship between the mathematical properties of LES models and the numerical methods used for their implementation. In last years it is more and more common the idea in the scientific community, especially in the numerical community, that turbulence models and stabilization techniques play a very similar role. Methodologies used to simulate turbulent flows, RANS or LES approaches, are based on the same concept: unability to simulate a turbulent flow using a finite discretization in time and space. Turbulence models introduce additional information (impossible to be captured by the approximation technique used in the simulation) to obtain physically coherent solutions. On the other side, numerical methods used for the integration of partial differential equations (PDE) need to be modified in order to able to reproduce solutions that present very high localized gradients. These modifications, known as stabilization techniques, make possible to capture these sharp and localized changes of the solution. According with previous paragraphs, the following natural question appears: Is it possible to reinterpret stabilization methods as turbulence models? This question suggests a possible principle of duality between turbulence modelling and numerical stabilization. More than to share certain properties, actually, it is suggested that the numerical stabilization can be understood as turbulence. The opposite will occur if turbulence models are only necessary due to discretization limitations instead of a need for reproducing the physical behaviour of the flow. Finally: can turbulence models be understood as a component of a general stabilization method?

  Abstract
  One of the aims of this text is to show some important results in LES modelling and to identify which are main mathematical problems for the development of a complete theory. [...]

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• An alpha-adaptive approach for stabilized finite element solution of advective-diffusive problems with sharp gradients

  E. Oñate, J. García-Espinosa, S. Idelsohn

  (1998). New Advances in Adaptive Computational Methods in Mechanics, P. Ladeveze and J.T. Oden (Eds.), Elsevier

  
  

  Abstract

  In this paper the FIC method is used as the basis for a new “alpha-adaptive” procedure (where alpha denotes the stabilization parameters) for obtaining stable solution in advective-diffusive problems where arbitrary sharp transverse gradients are present. The new stabilization thechnique can be viewed as an alternative class of adaptive methods where the numerical solution is enhanced by searching “adaptively” the optimal value of the streamline and transverse (crosswing) stabilization parameters while keeping the mesh and the finite element approximation unchanged. Indeed the basic alpha-adaptive process can be enhanced by combining it with standard h, p or hp adaptive schemes. In the first part of the paper the basis of the FIC stabilized method for advectivediffusive problems are explained. Next the algorithm for computing the streamline and transverse stabilization parameters via the new “alpha-adaptive” procedure is described. Finally, the efficiency and accuracy of the new approach are shown in two examples of application.

  Abstract
  In this paper the FIC method is used as the basis for a new “alpha-adaptive” procedure (where alpha denotes the stabilization parameters) for obtaining stable [...]

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• Ship hydrodynamics

  E. Oñate, J. García-Espinosa, S. Idelsohn

  (2004). Encyclopedia of Computational Mechanics, E. Stein, R. de Borst and T.J.R. Hughes (Eds.), John Wiley & Sons Ltd, Vol. 3, Chapter 18, pp. 579 - 607

  
  

  Abstract

  This chapter presents an overview of some computational methods for analysis of ship hydrodynamics problems. Attention is focused on the description of a stabilized finite element formulation derived via a finite calculus procedure. Both arbitrary Lagrangian-Eulerian (ALE) and fully Lagrangian forms are presented. Details of the treatment of the free-surface waves and the interaction between the ship structure and the sea water are also given. Examples of application to a variety of ship hydrodynamics problems are shown.

  Abstract
  This chapter presents an overview of some computational methods for analysis of ship hydrodynamics problems. Attention is focused on the description of a stabilized finite [...]

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• Computational Analysis Tools

  J. García-Espinosa

  Open Access Repository of the FIBRESHIP project (2019). 4

  
  

  Abstract

  This presentation was made at the Fibreship dissemination event hold at the Barcelona School of Nautical Studies (21st May 2019, Barcelona). It shows the advances made in the project regarding the development of different analysis tools to support design and inspection of large length FRP based ships.

  Abstract
  This presentation was made at the Fibreship dissemination event hold at the Barcelona School of Nautical Studies (21st May 2019, Barcelona). It shows the advances made [...]

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Articles (Documents not available in Scipedia)

• Estudio dinámico de líneas de fondeo en plataformas flotantes de aerogeneradores marinos

  J. García-Espinosa

  Ingeniería naval, 66-72, 2014

• Avances en el desarrollo de un modelo de elementos finitos para evaluación de un buque de efecto superficie

  J. García-Espinosa, B. Serván, D. Di Capua, P.A. Ubach, E. Oñate

  Ingeniería naval, 922: 68-73

• Estudio del Comportamiento Dinámico Acoplado en Estructuras Offshore

  JEG Romero, BZ Parra, JG Espinosa, JAE Pérez

  Anuario de Jóvenes Investigadores, 39-41, 2014

• Prediction of total resistance coefficients using neural networks

  I Ortigosa, R López, J García

  Journal of Maritime Research 6 (3), 15-26

• Dynamic modelling of mooring for floating offshore structures

  JE Gutiérrez Romero, B Zamora Parra, J García Espinosa, J Esteve

  Computational Methods in Marine Engineering V-Proceedings of the 5th ..., 2013

• Desarrollo de un conjunto de herramientas para el análisis acoplado de aerogeneradores en alta mar

  JE Gutiérrez Romero, B Zamora, J García Espinosa, J Esteve Pérez

  Ingeniería naval, 62-75, 2013

• Stabilized finite element methods for convection-diffusion-reaction, Helmholtz and Stokes problems

  P Nadukandi

  Universitat Politècnica de Catalunya, 2011

• A family of residual‐based stabilized finite element methods for Stokes flows

  E Oñate, P Nadukandi, SR Idelsohn, J García, C Felippa

  International Journal for Numerical Methods in Fluids 65 (1‐3), 106-134, 2011

• Experiencias en el desarrollo y aplicación de herramientas de cálculo y verificación de estructuras marinas para generación de energía

  J García Espinosa, B Serván Camas, D Sá

  49º Congreso de Ingeniería Naval e Industria Marítima, 1-16, 2010

• Análisis estructural del efecto de explosiones a bordo de buques de pasaje

  J García-Espinosa, D Di Capua, D Sá, S Honrubia, F Viejo, E Oñate, R Marí, ...

  Ingeniería naval, 105-114, 2007

• ODD Level Set: A new method for simulation of free surface problems

  JG Espinosa, AV Tomás

  Journal of maritime research 3 (1), 27-40, 2006

• Análisis CFD del movimiento de balance de un portacontenedores

  J García-Espinosa, E Oñate, JB Helmers, MR Chakkor

  Ingeniería Naval, abril, 2004

• Ship hydrodynamics

  E Onate, J García, SR Idelsohn

  Encyclopedia of computational mechanics, 2004

• A methodology for analysis of fluid-structure interaction accounting for free surface waves

  E Oñate, J García, S Idelsohn

  European Conference on Computational Mechanics (ECCM99), 1999

• A stabilized numerical method for analysis of ship hydrodynamics

  J García, E Oñate, H Sierra, C Sacco, S Idelsohn

  Computational fluid dynamics'98, 664-669, 1998

• An alpha-adaptive approach for stabilized finite element solution of advective-diffusive problems with sharp gradients

  E Onate, J García-Espinosa, S Idelsohn

  Computational fluid dynamics'98, 748-753, 1998

• On the stabilization of numerical solution for advective-diffusive transport and fluid flow problems

  E Oñate, J García, S Idelsohn

  Centro Internacional de Métodos Numéricos en Ingeniería, 1996

Books, book chapters and edited books (Documents not available in Scipedia)

• MARINE 2011, IV International Conferencn Marine Engineering: Selected Papers

  L. Eca, E. Oñate, J. García-Espinosa, T. Kvamsdal, P. Bergan

  Springer

• Fluid-Structure interaction applied to blood flow simulations

  E. Soudah, E. Oñate, J. García-Espinosa, J. S. Pérez, A. Mena, E. Heindenreich, J. F. Rodríguez, M. A. Martínez, M. Doblaré

  Advances in Computational Vision and Medical Image Processing, Springer

• Computational Methods in Marine Engineering III (MARINE 2009)

  P. Bergan, B. Pettersen, T. Kvamsdal, E. Oñate, J. García-Espinosa

  CIMNE

• Computational Methods in Marine Engineering II (MARINE 2007)

  P. Bergan, J. García-Espinosa, P. Kvamsdal, T. Kvamsdal, E. Oñate

  CIMNE

• LES turbulence models. Relation with stabilized numerical methods

  A. Valls, J. Garcia-Espinosa, E. Oñate

  Models, Experiments and Computation in Turbulence, CIMNE

• Computational Methods in Marine Engineering (MARINE 2005)

  P. Bergan, J. García-Espinosa, E. Oñate, T. Kvamsdal

  CIMNE

• A general stabilized formulation for incompressible fluid flow using finite calculus and the finite element method

  E. Onate, J. Garcia-Espinosa, G. Bugeda, S.R. Idelsohn

  Fluid dynamics and aeronautics new challenges: a book dedicated to Pierre Perrier. J. Periaux, D. Chamption, O. Pironneau, P.H. Thomas, eds.

Conference papers and presentations (Documents not available in Scipedia)

• A finite element method for fluid-structure interaction with surface waves

  J. Garcia-Espinosa and E. Oñate

  Proceedings of the European Conference on Computational Mechanics (ECCM 2001)

• Finite element analysis of incompressible flows with free surface waves using a finite calculus formulation

  E. Oñate, J. García-Espinosa

  Proceedings of the VI European Congress in Computational Methods in Applied Sciences and Engineering (ECCOMAS 2001)

Technical reports, thesis and other (Documents not available in Scipedia)

• Desarrollo de herramientas de autoaprendizaje multimedia para cálculo de estructuras por ordenador en ingeniería

  J. García-Espinosa, J. Martínez, D. Yebra, M. Cervera Ruiz, E. Oñate, S. Oller, B. Suárez

  Universitat Politècnica de Catalunya. Institut de Ciències de l'Educació, 2013