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  • Advances in the development of a FEM model for evaluation of a surface effect ship including skirt dynamics

     Garcia Espinosa, Julio; Serván Camas, Borja; Di Capua, Daniel; Ubach Fuentes, Pere-Andreu; Oñate Ibáñez de Navarra, Eugenio
    New frontiers (SNAMES Annual Journal)
    Vol. 34th Annual Journal, num. 2012/2013, p. 27-34
    Date of publication: 2013-06-01
    Journal article

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    This paper shows the recent work of the authors in the development of a time-domain FEM model for evaluation of a SES including skirt dynamics. In this work, a potential flow approach along with a stream-line integration of the free surface is used. The paper focuses on the fluid-structure algorithm that has been developed to allow the simulation of the complex and highly dynamic behavior of the seals in the interface between the air cushion, and the water. The algorithm is based, on one side, on a staggered explicit algorithm, using a TCP/IP sockets link, able to communicate pressure forces and displacements of the seals at memory level and, on the other side, on an innovative wetting and drying scheme able to predict the water action on the seals. Several cases of the XR-1B T-Craft model have been studied to demonstrate the developed algorithm.

  • Advances in the development of a FEM model for evaluation of a Surface-Effect Ship (SES) including skirt dynamics

     Garcia Espinosa, Julio; Serván Camas, Borja; Di Capua, Daniel; Ubach Fuentes, Pere-Andreu; Oñate Ibáñez de Navarra, Eugenio
    Ingeniería naval
    Vol. 1, num. 920, p. 86-91
    Date of publication: 2013-12-01
    Journal article

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    The Innovative Naval Prototype Transformable Craft (T-Craft) is a novel United States Navy concept for a seabase-to-shore connector, operative in multiple modes. It can self deploy from an intermediate support base to the sea base and then be used as a high speed connector from the sea base to the shore, transporting wheeled and tracked vehicles and other heavy equipment and cargo through the surf zone and onto the beach,where it can discharge its cargo without the need for a port. T-Craft has been conceived as a surface-effect ship (SES) with a fanactivated air cushion between two rigid hulls, allowing the vessel to operate in modes of full displacement, partial air-cushion support, and full aircushion support. This paper shows the recent work of the authors in the development of a time-domain FEM model for evaluation of a T-Craft seakeeping and maneuvering, including skirt dynamics. In this work, a potential flow approach along with a stream-line integration of the free surface is used. The paper focuses on the fluid-structure algorithm that has been developed to allow the simulation of the complex and highly dynamic behavior of the seals in the interface between the air cushion, and the water.The algorithm is based, on one side, on a staggered explicit algorithm, using a TCP/IP sockets link, able to communicate pressure forces and displacements of the seals at memory level and, on the other side, on an innovative wetting and drying scheme able to predict the water action on the seals. Several cases of the XR-1B T-Craft model have been studied to demonstrate the developed algorithm. This research has been sponsored by the Office of Naval Research under Grant N62909-10-1-7053.

  • 52º Congreso de Ingeniería Naval e Industria Marítima

     Gutiérrez, José Enrique; Garcia Espinosa, Julio; Zamora, Blas; Esteve, Jerónimo
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  • 52º Congreso de Ingeniería Naval e Industria Marítima

     Garcia Espinosa, Julio; Serván Camas, Borja; Di Capua, Daniel; Ubach Fuentes, Pere-Andreu; Oñate Ibáñez de Navarra, Eugenio
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  • Advances in the development of a time-domain unstructured finite element method for the analysis of waves and floating structures interaction

     Serván Camas, Borja; Garcia Espinosa, Julio
    DOI: 10.1007/978-94-007-6143-8
    Date of publication: 2013-05-02
    Book chapter

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    Being capable of predicting wave-structure interaction in the time domain is of great interest for the offshore industry. However, most computer programs used in the industry work in the frequency domain. Therefore, the main objective of this work is the development a time domain solver based on the finite element method capable of solving wave-structure interaction problems using unstructured meshes. We found good agreement between the numerical results we obtained and analytical solutions as well as numerical solutions obtained by other numerical method.

    We present some developments in the Particle Finite Element Method (PFEM) for the solution of complex coupled problems in marine, naval and harbour engineering involving fluid-soil-structure interaction (FSSI). The PFEM uses an updated Lagrangian description to model the motion of nodes (particles) in a continuum domain containing fluid, soil/rock and structures subdomains. A mesh connects the nodes defining the discretized domain where the governing equations for each of the constituent materials are solved with the FEM. The stabilization for dealing with an incompressibility material is introduced via the finite calculus (FIC) method. An incremental iterative scheme for solving the non linear transient FSSI problem is described. The procedure to model frictional contact conditions and material erosion at fluid-solid and solid-solid interfaces is described. We present examples of application of the PFEM to solve FSSI problems in marine, naval and harbour engineering such as the motion of rocks by water streams, the stability of breakwaters and constructions under sea waves, the sinking of ships and the collision of a ship with ice blocks.

  • On the interpolation of normal vectors for triangle meshes

     Ubach Fuentes, Pere-Andreu; Estruch Tena, Carlos; Garcia Espinosa, Julio
    International journal for numerical methods in engineering
    Vol. 96, num. 4, p. 247-268
    DOI: 10.1002/nme.4567
    Date of publication: 2013
    Journal article

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    This paper analyzes the problem arising from the need to assign information about the normal vectors to the surface at the nodes of a mesh of triangles. Meshes of triangles do not have normals uniquely defined at the nodes. A widely used technique to compute the normal direction at any given node is to compute the weighted average of the normals of each surrounding triangle. The present study proposes new weighting factors to compute the normal directions at the nodes of the mesh of triangles of a general surface. Previous weights found in the literature used the geometric dimensions of the triangles themselves to design the weighting factors. The new factors are proposed using the triangles' circumscribed circles dimensions. The new weights provide superior results than the ones obtained by previous best practices for a wide range of surfaces. An advanced framework based on the approachability of smooth surfaces by quadrics is presented and used. This framework helps to understand the improved performance of the presented factors with respect to other factors found in the literature. A comprehensive numerical comparison analysis is performed, and the most precise of all factors is clearly identified.

    This paper analyzes the problem arising from the need to assign information about the normal vectors to the surface at the nodes of a mesh of triangles. Meshes of triangles do not have normals uniquely defined at the nodes. A widely used technique to compute the normal direction at any given node is to compute the weighted average of the normals of each surrounding triangle. The present study proposes new weighting factors to compute the normal directions at the nodes of the mesh of triangles of a general surface. Previous weights found in the literature used the geometric dimensions of the triangles themselves to design the weighting factors. The new factors are proposed using the triangles’ circumscribed circles dimensions. The new weights provide superior results than the ones obtained by previous best practices for a wide range of surfaces. An advanced framework based on the approachability of smooth surfaces by quadrics is presented and used. This framework helps to understand the improved performance of the presented factors with respect to other factors found in the literature. A comprehensive numerical comparison analysis is performed, and the most precise of all factors is clearly identified.

  • Accelerated 3D multi-body seakeeping simulations using unstructured finite elements

     Serván Camas, Borja; Garcia Espinosa, Julio
    Journal of computational physics
    Vol. 252, p. 382-403
    DOI: 10.1016/j.jcp.2013.06.023
    Date of publication: 2013-11-01
    Journal article

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    Being capable of predicting seakeeping capabilities in the time domain is of great interest for the marine and offshore industries. However, most computer programs used work in the frequency domain, with the subsequent limitation in the accuracy of their model predictions. The main objective of this work is the development of a time domain solver based on the finite element method capable of solving multi-body seakeeping problems on unstructured meshes. In order to achieve this objective, several techniques are combined: the use of an efficient algorithm for the free surface boundary conditions, the use of deflated conjugate gradients, and the use of a graphic processing unit for speeding up the linear solver. The results obtained by the developed model showed good agreement with analytical solutions, experimental data for an actual offshore structure model, as well as numerical solutions obtained by other numerical method. Also, a simulation with sixteen floating bodies was carried out in an affordable CPU time, showing the potential of this approach for multi-body simulation

    Being capable of predicting seakeeping capabilities in the time domain is of great interest for the marine and offshore industries. However, most computer programs used work in the frequency domain, with the subsequent limitation in the accuracy of their model predictions. The main objective of this work is the development of a time domain solver based on the finite element method capable of solving multi-body seakeeping problems on unstructured meshes. In order to achieve this objective, several techniques are combined: the use of an efficient algorithm for the free surface boundary conditions, the use of deflated conjugate gradients, and the use of a graphic processing unit for speeding up the linear solver. The results obtained by the developed model showed good agreement with analytical solutions, experimental data for an actual offshore structure model, as well as numerical solutions obtained by other numerical method. Also, a simulation with sixteen floating bodies was carried out in an affordable CPU time, showing the potential of this approach for multi-body simulation.

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

     Gutiérrez Romero, José Enrique; Zamora, Blas; Garcia Espinosa, Julio; Esteve Pérez, Jerónimo
    Ingeniería naval
    num. 910, p. 62-75
    Date of publication: 2013-01-31
    Journal article

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    Existe una urgente necesidad en el estudio del comportamiento de aerogeneradores en alta mar. En este trabajo se presentan dos nuevas herramientas de ingeniería, de libre acceso, denominadas FASTLognoter y MorisonForm. La primera de ellas emplea como base en su desarrollo, las rutinas FAST (simulador aeroelástico de aerogeneradores, desarrollado por NREL), añadiendo nuevas capacidades y preprocesadores. La segunda herramienta, MorisonForm se desarrolla para obtener la respuesta dinámica de plataformas empleadas como soporte en las diferentes propuestas existentes para aerogeneradores en alta mar. La integración de esas dos herramientas ofrece un software útil, que permiten llevar a cabo un análisis acoplado en este tipo de sistemas, de una manera sencilla. Una ventaja relevante de estas herramientas es la posibilidad de analizar un gran número de casos, contemplando diversas alternativas de diseño Se presenta además, el proceso de análisis acoplado (cargas aerodinámicas más cargas hidrodinámicas),mediante el uso de estas herramientas. El estudio de la influencia de diversos parámetros puede llevar a un diseño óptimo.

  • MARINE 2011, IV International Conference on Computational Methods in Marine Engineering

    DOI: 10.1007/978-94-007-6143-8
    Date of publication: 2013-05-02
    Book

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    Being capable of predicting wave-structure interaction in the time domain is of great interest for the offshore industry. However, most computer programs used in the industry work in the frequency domain. Therefore, the main objective of this work is the development a time domain solver based on the finite element method capable of solving wave-structure interaction problems using unstructured meshes. We found good agreement between the numerical results we obtained and analytical solutions as well as numerical solutions obtained by other numerical method.

    We present some developments in the Particle Finite Element Method (PFEM) for the solution of complex coupled problems in marine, naval and harbour engineering involving fluid-soil-structure interaction (FSSI). The PFEM uses an updated Lagrangian description to model the motion of nodes (particles) in a continuum domain containing fluid, soil/rock and structures subdomains. A mesh connects the nodes defining the discretized domain where the governing equations for each of the constituent materials are solved with the FEM. The stabilization for dealing with an incompressibility material is introduced via the finite calculus (FIC) method. An incremental iterative scheme for solving the non linear transient FSSI problem is described. The procedure to model frictional contact conditions and material erosion at fluid-solid and solid-solid interfaces is described. We present examples of application of the PFEM to solve FSSI problems in marine, naval and harbour engineering such as the motion of rocks by water streams, the stability of breakwaters and constructions under sea waves, the sinking of ships and the collision of a ship with ice blocks.

  • Dynamic modelling of mooring for floating offshore structuresmarine 2013

     Gutiérrez Romero, José Enrique; Zamora Parra, Blas; Garcia Espinosa, Julio; Esteve, J
    International Conference on Computational Methods in Marine Engineering
    p. 309-319
    Presentation's date: 2013-05
    Presentation of work at congresses

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    There is a demand to develop and evaluate new concepts for offshore structures for harnessing ocean energy. Tools capable of calculating the behaviour of this kind of structures are also requestedby the industry. An accurate analysis comprises fully coupled simulations and the use of complex models for non-linear dynamics analysis, including the modellingofmooring lines onfloating offshore structures. In opposite of quasi-staticmodellingof mooring lines such as catenary lines [1],time-dependent models [2, 3] present some advantages.This workpresents a dynamic modelof mooring lines for deep-water structures using LMM (Lumped Mass Method)[4, 5] formulation and its application on differentkinds of floating devices. First, the mathematical model for mooring lines is presented. Then anapplication tool based on that mathematical model is showed. This tool is linked to the time-domain seakeeping solver SeaFEM [6]. The resulting model is able to obtain a fully coupled analysis of seakeeping and mooring dynamics of floating offshore structures. A preliminary study of mooring dynamics is presented over differentsolutions and configurations of mooring lines for severalfloating devices. Furthermore, an optimal design of mooring line configurations for differentsolutions of floating structures can be achieved.This work also presents the study of differentfloating devices under several sea wave conditions. Finallysome conclusions are remarked, and the future research lines are presented.

  • Advances in the development of a FEM model for evaluation of a Surface-Effect Ship (SES) including skirt dynamics

     Garcia Espinosa, Julio; Serván Camas, Borja; Di Capua, Daniel; Ubach Fuentes, Pere-Andreu; Oñate Ibáñez de Navarra, Eugenio
    Congreso de Ingeniería Naval e Industria Marítima
    p. 1-13
    Presentation's date: 2013-10-24
    Presentation of work at congresses

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    This paper shows the recent work of the authors in the development of a time-domain FEM model for evaluation of a SES including skirt dynamics. In this work, a potential flow approach along with a stream-line integration of the free surface is used. The paper focuses on the fluid-structure algorithm that has been developed to allow the simulation of the complex and highly dynamic behavior of the seals in the interface between the air cushion, and the water. The algorithm is based, on one side, on a staggered explicit algorithm, using a TCP/IP sockets link, able to communicate pressure forces and displacements of the seals at memory level and, on the other side, on an innovative wetting and drying scheme able to predict the water action on the seals. Several cases of the XR-1B SES model have been studied to demonstrate the developed algorithm.

    El “Innovative Naval Prototype Transformable Craft” (T-Craft) es un nuevo concepto de buque desarrollado por la marina de los Estados Unidos de América para la conexión de una base en alta mar con tierra. El TCraft puede operar en múltiple modos, usándose para conectar una base intermedia de soporte con la principal, y luego ser utilizado como conexión de alta velocidad con la costa, transportando vehículos y otros equipos y carga pesada hasta la playa. El T-Craft se ha concebido como un buque de efecto superficie (Surface-Effect Ship, SES) con un colchón de aire activo entre dos cascos rígidos, que permite al buque operar a desplazamiento completo, con soporte parcial del colchón o con el colchón plenamente activo. Este artículo presenta el trabajo reciente de los autores en el desarrollo de un modelo de evaluación del comportamiento en la mar y la maniobrabilidad del T-Craft, incluyendo la interacción del faldón. Este modelo está basado en la resolución de las ecuaciones de flujo potencial en el dominio del tiempo, mediante el método de los elementos finitos, integrando la superficie libre a lo largo de las líneas de corriente. Este artículo revisa el algoritmo de interacción fluido estructura desarrollado para la simulación de la compleja dinámica de los sellos, en la interfaz entre el colchón de aire y el agua. El algoritmo se basa, por una parte, en un algoritmo explícito alternado que permite la comunicación entre los solvers fluido-dinámico y estructural mediante TCP-IP sockets, intercambiando fuerzas de presión y desplazamientos en los sellos durante la ejecución, y por otra parte, en un innovador esquema de secado-mojado que permite predecir la interacción del agua con los sellos. Se incluyen varios casos de aplicación de la metodología desarrollada sobre el modelo l XR-1B.

  • Perfomance evaluation of the air cushion and seals of a SES in presence of waves and maneuvering in shallow water

     Garcia Espinosa, Julio; Serván Camas, Borja; Di Capua, Daniel; Ubach Fuentes, Pere-Andreu; Oñate Ibáñez de Navarra, Eugenio
    Congreso de Métodos Numéricos en Ingeniería
    p. 1806-1820
    Presentation's date: 2013-06-26
    Presentation of work at congresses

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  • 51 Congreso de Ingeniería Naval e Industria Marítima

     Gutiérrez Romero, José Enrique; Zamora Parra, Blas; Garcia Espinosa, Julio; Esteve Pérez, Jerónimo
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  • Development of a decision support system for the design and adjustment of sailboat rigging

     Ortigosa Barragán, Inmaculada
    Department of Nautical Sciences and Engineering, Universitat Politècnica de Catalunya
    Theses

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  • A Petrov-Galerkin formulation for the alpha interpolation of FEM and FDM stencils: Applications to the Helmholtz equation

     Nadukandi, Prashanth; Oñate Ibáñez de Navarra, Eugenio; Garcia Espinosa, Julio
    International journal for numerical methods in engineering
    Vol. 89, num. 11, p. 1367-1391
    DOI: 10.1002/nme.3291
    Date of publication: 2012-03-16
    Journal article

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  • Tool development based on FAST for performing design optimization of offshore wind turbines: FASTLognoter

     Gutiérrez Romero, José Enrique; Zamora, Blas; Garcia Espinosa, Julio; Peyrau, María R.
    Renewable energy
    num. 55, p. 69-78
    DOI: 10.1016/j.renene.2012.12.026
    Date of publication: 2012-12-31
    Journal article

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  • A high-resolution Petrov-Galerkin method for the convection-diffusion-reaction problem. Part II: a multidimensional extension

     Nadukandi, Prashanth; Oñate Ibáñez de Navarra, Eugenio; Garcia Espinosa, Julio
    Computer methods in applied mechanics and engineering
    Vol. 213-216, p. 327-352
    DOI: 10.1016/j.cma.2011.10.003
    Date of publication: 2012-03
    Journal article

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    A multidimensional extension of the HRPG method (doi:10.1016/j.cma.2009.10.009) using the lowest order block finite elements is presented. First, we design a nondimensional element number that quantifies the characteristic layers which are found only in higher dimensions. This is done by matching the width of the characteristic layers to the width of the parabolic layers found for a fictitious 1D reaction¿diffusion problem. The nondimensional element number is then defined using this fictitious reaction coefficient, the diffusion coefficient and an appropriate element size. Next, we introduce anisotropic element length vectors li and the stabilization parameters ai, ßi are calculated along these li. Except for the modification to include the new dimensionless number that quantifies the characteristic layers, the definitions of ai, ßi are a direct extension of their counterparts in 1D. Using ai, ßi and li, objective characteristic tensors associated with the HRPG method are defined. The numerical artifacts across the characteristic layers are manifested as the Gibbs phenomenon. Hence, we treat them just like the artifacts formed across the parabolic layers in the reaction-dominant case. Several 2D examples are presented that support the design objective¿stabilization with high-resolution.

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

     Nadukandi, Prashanth; Oñate Ibáñez de Navarra, Eugenio; Garcia Espinosa, Julio
    Date of publication: 2012
    Book

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    We present three new stabilized finite element (FE) based Petrov¿Galerkin methods for the convection¿diffusion¿reaction (CDR), the Helmholtz and the Stokes problems, respectively.

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

     Gutiérrez Romero, José Enrique; Zamora Parra, Blas; Garcia Espinosa, Julio; Esteve Pérez, Jerónimo
    Congreso de Ingeniería Naval e Industria Marítima
    p. 1-29
    Presentation's date: 2012-10-18
    Presentation of work at congresses

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  • Premi AINE per la capacitat d¿innovar l¿enginyeria naval

     Garcia Espinosa, Julio; Oñate Ibáñez de Navarra, Eugenio
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  • Q-00028

     Garcia Espinosa, Julio
    Competitive project

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  • Stabilized finite element methods for convection-diffusion-reaction, helmholtz and stokes problems  Open access

     Nadukandi, Prashanth
    Department of Strength of Materials and Structural Engineering, Universitat Politècnica de Catalunya
    Theses

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    We present three new stabilized finite element (FE) based Petrov-Galerkin methods for the convection-diffusionreaction (CDR), the Helmholtz and the Stokes problems, respectively. The work embarks upon a priori analysis of a consistency recovery procedure for some stabilization methods belonging to the Petrov- Galerkin framework. It was ound that the use of some standard practices (e.g. M-Matrices theory) for the design of essentially non-oscillatory numerical methods is not appropriate when consistency recovery methods are employed. Hence, with respect to convective stabilization, such recovery methods are not preferred. Next, we present the design of a high-resolution Petrov-Galerkin (HRPG) method for the CDR problem. The structure of the method in 1 D is identical to the consistent approximate upwind (CAU) Petrov-Galerkin method [doi: 10.1016/0045-7825(88)90108-9] except for the definitions of he stabilization parameters. Such a structure may also be attained via the Finite Calculus (FIC) procedure [doi: 10.1 016/S0045-7825(97)00119-9] by an appropriate definition of the characteristic length. The prefix high-resolution is used here in the sense popularized by Harten, i.e. second order accuracy for smooth/regular regimes and good shock-capturing in non-regular re9jmes. The design procedure in 1 D embarks on the problem of circumventing the Gibbs phenomenon observed in L projections. Next, we study the conditions on the stabilization parameters to ircumvent the global oscillations due to the convective term. A conjuncture of the two results is made to deal with the problem at hand that is usually plagued by Gibbs, global and dispersive oscillations in the numerical solution. A multi dimensional extension of the HRPG method using multi-linear block finite elements is also presented. Next, we propose a higher-order compact scheme (involving two parameters) on structured meshes for the Helmholtz equation. Making the parameters equal, we recover the alpha-interpolation of the Galerkin finite element method (FEM) and the classical central finite difference method. In 1 D this scheme is identical to the alpha-interpolation method [doi: 10.1 016/0771 -050X(82)90002-X] and in 2D choosing the value 0.5 for both the parameters, we recover he generalized fourth-order compact Pade approximation [doi: 10.1 006/jcph.1995.1134, doi: 10.1016/S0045- 7825(98)00023-1] (therein using the parameter V = 2). We follow [doi: 10.1 016/0045-7825(95)00890-X] for the analysis of this scheme and its performance on square meshes is compared with that of the quasi-stabilized FEM [doi: 10.1016/0045-7825(95)00890-X]. Generic expressions for the parameters are given that guarantees a dispersion accuracy of sixth-order should the parameters be distinct and fourth-order should they be equal. In the later case, an expression for the parameter is given that minimizes the maximum relative phase error in 2D. A Petrov-Galerkin ormulation that yields the aforesaid scheme on structured meshes is also presented. Convergence studies of the error in the L2 norm, the H1 semi-norm and the I ~ Euclidean norm is done and the pollution effect is found to be small.

    Presentamos tres nuevos metodos estabilizados de tipo Petrov- Galerkin basado en elementos finitos (FE) para los problemas de convecci6n-difusi6n- reacci6n (CDR), de Helmholtz y de Stokes, respectivamente. El trabajo comienza con un analisis a priori de un metodo de recuperaci6n de la consistencia de algunos metodos de estabilizaci6n que pertenecen al marco de Petrov-Galerkin. Hallamos que el uso de algunas de las practicas estandar (por ejemplo, la eoria de Matriz-M) para el diserio de metodos numericos esencialmente no oscilatorios no es apropiado cuando utilizamos los metodos de recu eraci6n de la consistencia. Por 10 tanto, con res ecto a la estabilizaci6n de conveccion, no preferimos tales metodos de recuperacion . A continuacion, presentamos el diser'io de un metodo de Petrov-Galerkin de alta-resolucion (HRPG) para el problema CDR. La estructura del metodo en 10 es identico al metodo CAU [doi: 10.1016/0045-7825(88)90108-9] excepto en la definicion de los parametros de estabilizacion. Esta estructura tambien se puede obtener a traves de la formulacion del calculo finito (FIC) [doi: 10.1 016/S0045- 7825(97)00119-9] usando una definicion adecuada de la longitud caracteristica. El prefijo de "alta-resolucion" se utiliza aqui en el sentido popularizado por Harten, es decir, tener una solucion con una precision de segundo orden en los regimenes suaves y ser esencialmente no oscilatoria en los regimenes no regulares. El diser'io en 10 se embarca en el problema de eludir el fenomeno de Gibbs observado en las proyecciones de tipo L2. A continuacion, estudiamos las condiciones de los parametros de estabilizacion para evitar las oscilaciones globales debido al ermino convectivo. Combinamos los dos resultados (una conjetura) para tratar el problema COR, cuya solucion numerica sufre de oscilaciones numericas del tipo global, Gibbs y dispersiva. Tambien presentamos una extension multidimensional del metodo HRPG utilizando los elementos finitos multi-lineales. fa. continuacion, proponemos un esquema compacto de orden superior (que incluye dos parametros) en mallas estructuradas para la ecuacion de Helmholtz. Haciendo igual ambos parametros, se recupera la interpolacion lineal del metodo de elementos finitos (FEM) de tipo Galerkin y el clasico metodo de diferencias finitas centradas. En 10 este esquema es identico al metodo AIM [doi: 10.1 016/0771 -050X(82)90002-X] y en 20 eligiendo el valor de 0,5 para ambos parametros, se recupera el esquema compacto de cuarto orden de Pade generalizada en [doi: 10.1 006/jcph.1 995.1134, doi: 10.1 016/S0045-7825(98)00023-1] (con el parametro V = 2). Seguimos [doi: 10.1 016/0045-7825(95)00890-X] para el analisis de este esquema y comparamos su rendimiento en las mallas uniformes con el de "FEM cuasi-estabilizado" (QSFEM) [doi: 10.1016/0045-7825 (95) 00890-X]. Presentamos expresiones genericas de los para metros que garantiza una precision dispersiva de sexto orden si ambos parametros son distintos y de cuarto orden en caso de ser iguales. En este ultimo caso, presentamos la expresion del parametro que minimiza el error maxima de fase relativa en 20. Tambien proponemos una formulacion de tipo Petrov-Galerkin ~ue recupera los esquemas antes mencionados en mallas estructuradas. Presentamos estudios de convergencia del error en la norma de tipo L2, la semi-norma de tipo H1 y la norma Euclidiana tipo I~ y mostramos que la perdida de estabilidad del operador de Helmholtz ("pollution effect") es incluso pequer'ia para grandes numeros de onda. Por ultimo, presentamos una coleccion de metodos FE estabilizado para el problema de Stokes desarrollados a raves del metodo FIC de primer orden y de segundo orden. Mostramos que varios metodos FE de estabilizacion existentes y conocidos como el metodo de penalizacion, el metodo de Galerkin de minimos cuadrados (GLS) [doi: 10.1016/0045-7825(86)90025-3], el metodo PGP (estabilizado a traves de la proyeccion del gradiente de presion) [doi: 10.1 016/S0045-7825(96)01154-1] Y el metodo OSS (estabilizado a traves de las sub-escalas ortogonales) [doi: 10.1016/S0045-7825(00)00254-1] se recuperan del marco general de FIC. Oesarrollamos una nueva familia de metodos FE, en adelante denominado como PLS (estabilizado a traves del Laplaciano de presion) con las formas no lineales y consistentes de los parametros de estabilizacion. Una caracteristica distintiva de la familia de los metodos PLS es que son no lineales y basados en el residuo, es decir, los terminos de estabilizacion dependera de los residuos discretos del momento y/o las ecuaciones de incompresibilidad. Oiscutimos las ventajas y desventajas de estas tecnicas de estabilizaci6n y presentamos varios ejemplos de aplicacion

  • Simulation of water circulation over a model of a submarine canyon using FIC-FEM numerical model

     Germán, Arnel; Garcia Espinosa, Julio; Espino Infantes, Manel; Maidana Silanes, Augusto
    Journal of waterway, port, coastal, and ocean engineering
    Vol. 138, num. 1, p. 22-29
    DOI: 10.1061/(ASCE)WW.1943-5460.0000105
    Date of publication: 2011-05-26
    Journal article

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

     Oñate Ibáñez de Navarra, Eugenio; Nadukandi, Prashanth; Idelsohn Barg, Sergio Rodolfo; Garcia Espinosa, Julio; Felippa, Carlos
    International journal for numerical methods in fluids
    Vol. 65, num. 1-3, p. 106-134
    DOI: 10.1002/fld.2468
    Date of publication: 2011-01
    Journal article

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  • A fourth-order compact scheme for the Helmholtz equation: Alpha-interpolation of FEM and FDM stencils

     Nadukandi, Prashanth; Oñate Ibáñez de Navarra, Eugenio; Garcia Espinosa, Julio
    International journal for numerical methods in engineering
    Vol. 86, num. 1, p. 18-46
    DOI: 10.1002/nme.3043
    Date of publication: 2011-04
    Journal article

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  • Development of stabilization methods in convective transport problems using finite calculus

     Nadukandi, Prashanth
    International Center for Numerical Methods in Engineering
    Theses

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    Advances in the development of a time-domain unstructured finite element method for the analysis of waves and floating structures interaction  Open access

     Serván Camas, Borja; Garcia Espinosa, Julio
    International Conference on Computational Methods in Marine Engineering
    p. 450-457
    Presentation's date: 2011-09-29
    Presentation of work at congresses

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    FAST Lognoter: Integración de herramientas para el cálculo de aerogeneradores  Open access

     Gutiérrez, José Enrique; Garcia Espinosa, Julio
    Congreso de Ingeniería Naval e Industria Marítima
    p. 1-40
    Presentation's date: 2011-10-27
    Presentation of work at congresses

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    El crecimiento de las energías renovables, y en concreto de la energía eólica marina, propician el desarrollo de herramientas que permitan un estudio completo del aerogenerador (‘Offshore’). Hasta el momento, se ha dedicado un gran esfuerzo al desarrollo de códigos que permitan un estudio profundo de los mismos. En este trabajo se presenta la herramienta FAST Lognoter, resultado de la integración de otras dos: por un lado del código FAST (Fatigue,Aerodynamics, Structures and Turbulence desarrollado por NREL, http://wind.nrel.gov), que es una completa herramienta para la simulación del cálculo aeroelástico, capaz de predecir las cargas extremas y de fatiga de aerogeneradores de 2 y 3 palas, y por el otro de Lognoter (desarrollado por Compass IS, http://www.compassis.com), una aplicación de propósito general para la gestión y creación de formularios en Ingeniería. La integración de las dos aplicaciones ha dado lugar a una herramienta completa y versátil, que se valida en este trabajo mediante casos documentados en la bibliografía.

  • Sistema de amarre de embarcaciones a una estructura fija

     Garcia Espinosa, Julio; Pegram, William James; Ribo Rodriguez, Ramon; Samaniego Navarro, Jose Jaime
    Date of request: 2011-12-22
    Invention patent

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  • A high-resolution Petrov-Galerkin method for the 1D convection-diffusion-reaction problem

     Nadukandi, Prashanth; Oñate Ibáñez de Navarra, Eugenio; Garcia Espinosa, Julio
    Computer methods in applied mechanics and engineering
    Vol. 199, num. 9-12, p. 525-546
    DOI: 10.1016/j.cma.2009.10.009
    Date of publication: 2010-01
    Journal article

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

     Garcia Espinosa, Julio; Serván Camas, Borja; Sá, Daniel
    Congreso de Ingeniería Naval e Industria Marítima
    p. 1-16
    Presentation's date: 2010-10-21
    Presentation of work at congresses

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  • SISTEMA DE APOYO A LA INVESTIGACION DEL ORIGEN DE VERTIDOS ILEGALES EN EL MAR

     Ortigosa Barragán, Inmaculada; Castells Sanabra, Marcel·la; Maidana Silanes, Augusto; Garcia Espinosa, Julio
    Competitive project

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  • Fluid-Structure interaction applied to blood flow simulations

     Oñate Ibáñez de Navarra, Eugenio; Garcia Espinosa, Julio; Soudah, E; Pérez, J S; Mena, A; Heidenreich, E; Rodríguez, J F; Doblaré, M
    Date of publication: 2009-02
    Book chapter

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  • Prediction of total resistance coefficients using neural networks  Open access

     Ortigosa Barragán, Inmaculada; Revilla Lopez, Guillermo; Garcia Espinosa, Julio
    Journal of maritime research
    Vol. 6, num. 3, p. 15-26
    Date of publication: 2009-12
    Journal article

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    The Holtrop & Mennen method is widely used at the initial design stage of ships for estimating the resistance of the ship (Holtrop and Mennen, 1982). The Holtrop & Mennen method provide a prediction of the total resistance’s components. In this work we present a neural network model which performs the same task as the Holtrop & Mennem’s method, for two of the total resistance’s components. A multilayer perceptron has been therefore trained to learn the relationship between the input (length-displacement ratio, prismatic coefficient, longitudinal position of the centre of buoyancy, after body form and Froude number) and the target variables (form factor and wave-making and wave-breaking resistance per unit weight of displacement). The network architecture with best generalization properties was obtained through an exhaustive validation analysis (Bishop, 1995). The results of this model have been compared against those provided by the Holtrop & Mennen method, and it was found that the quality of the prediction is improved over the entire range of data. The neural network provides an accurate estimation of two total resistance’s components with Froude number and hull geometry coefficients as variables.

  • Analysis of coastal flow near submarine canyons using Tdyn numerical model

     German, A.; Maidana, M.A.; Espino Infantes, Manel; Garcia Espinosa, Julio
    International Conference on Computational Methods in Marine Engineering
    p. 133-136
    Presentation's date: 2009-06-16
    Presentation of work at congresses

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  • Advances in the development of an unstructured fem solver for fluid-structure interaction problems in marine engineering  Open access

     Kvamsdal, Trond; Pettersen, B; Bergan, Päl; Oñate Ibáñez de Navarra, Eugenio; Garcia Espinosa, Julio
    International Conference on Computational Methods in Marine Engineering
    p. 1-4
    Presentation's date: 2009-06-17
    Presentation of work at congresses

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    This work presents different advances in the development of a formulation for fluid-structure interaction analysis in marine applications using the FIC stabilized finite element method (FEM). The free surface evolution is solved using of an overlapping domain decomposition concept in the statement of the problem. The work also presents a new mesh generation algorithm for unstructured meshed including boundary layer anisotropic refinement.

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    A calculation/simulation system of sails communicated in real time with wireless sensors  Open access

     Ortigosa Barragán, Inmaculada; Garcia Espinosa, Julio
    International Conference on Computational Methods in Marine Engineering
    p. 129-132
    Presentation's date: 2009-06-18
    Presentation of work at congresses

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    The model presented in this paper is part of the development and integration of a System to Support Decision (SAD) for assistance in the design and actuation of sails. The model is based on the union of a wireless sensor system, continuously connected to a calculation/simulation system. This system will predict the structural behavior and performance of the different configurations of the rigging of a sailing ship. The simulation software will be communicated in real time with wireless sensors and interfaces through suitable filters. The information gathered by the sensors, which are integrated into the structure of the boat, will be used in numerical algorithms to determine the efforts that are suffering the Structure and evaluate the overall performance of the sailboat. The system of calculation / simulation is made up of a model of structural calculation based on a quasi-static method with a formulation for large displacement typical of the finite element method, and includes models of membranes, cables and bars. And the starting point of the simulation tool of fluid dynamics is the method of vortices (contour elements). The algorithms are adapted so that they can make real-time data that offers the monitoring system. The software also has algorithms simulation maneuver with which you can change the position of the sails.

  • A new unstructured mesh FE method for the analysis of ship hydrodynamics

     Garcia Espinosa, Julio; Oñate Ibáñez de Navarra, Eugenio
    World Congress on Computational Mechanics
    Presentation's date: 2008-07-04
    Presentation of work at congresses

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  • Introducción al cálculo directo con Ramseries Naval

     Garcia Espinosa, Julio
    Espacio de Innovación del Salón Náutico Internacional de Barcelona
    Presentation's date: 2008-11-13
    Presentation of work at congresses

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  • Ramseries naval o por qué el cálculo directo de estructuras sustituye a los métodos tradicionales

     Garcia Espinosa, Julio
    Taller de Ingeniería Naval del Salón Náutico Internacional de Barcelona
    Presentation's date: 2008-11-13
    Presentation of work at congresses

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