gdbOF: A Debugging Tool for OpenFOAM

OpenFOAM® libraries are a great contribution to CFD community and a powerful way to create solvers and other tools. Nevertheless in this creative process a deep knowledge is needed concerning with classes structure, for value storage in geometric fields and also for matrices resulting from equation systems, becoming a hard task for debugging. To help in this process a new tool, called gdbOF, attachable to gdb (GNU debugger) is presented in this paper. It allows to analyze classes structure at debugging time. This application is implemented by gdb macros, these macros can access to code classes and also to their data in a transparent way, giving the requested information. This tool is tested for different application cases, such as the assemble and storage of matrices in a scalar advective–diffusive problem, non orthogonal correction methods in purely diffusive tests and multiphase solvers based on Volume of Fluid Method. In these tests several types of data are checked, such as: internal and boundary vector and scalar values from solution fields, fluxes in cell faces, boundary patches and boundary conditions. As additional features of this tool data dumping to file and a graphical monitoring of fields are presented. All these capabilities give to gdbOF a wide range of use not only in academic tests but also in real problems.Fil: Marquez Damian, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Gimenez, Juan Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Nigro, Norberto Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentin

The Pseudo-Direct Numerical Simulation Method considered as a Reduced Order Model

The multiscale method called Pseudo-Direct Numerical Simulation (P-DNS) is presented as a Reduced Order Model (ROM) aiming to solve problems obtaining similar accuracy to a solution with many degrees of freedom (DOF). The theoretical basis of P-DNS is other than any standard ROM. However, from a methodological point of view, P-DNS shares the idea of an offline computation, as ROM does, providing the set of coefficients, as a database or table, needed to solve the main problem. This work highlights the advantages and disadvantages of both methodologies. In particular, the drawback of the standard ROM concerning problems where space and time are not separated variables is discussed. The so-called Idelsohn’s benchmark is possibly the most elemental test that can be proposed to point out this drawback. This one-dimensional heat transfer problem with a moving heat source shows that, unlike ROMs, P-DNS can solve it by reducing the number of degrees of freedom as much as needed.Fil: Idelsohn, Sergio Rodolfo. Centre Internacional de Mètodes Numèrics En Enginyeria; España. Institució Catalana de Recerca i Estudis Avancats; España. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gimenez, Juan Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; Argentina. Centre Internacional de Mètodes Numèrics En Enginyeria; EspañaFil: Nigro, Norberto Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; Argentin

Technical and Regulatory Exigencies for Grid Connection of Wind Generation

Pollution problems such as the greenhouse effect as well as the high value and volatility of fuel prices have forced and accelerated the development and use of renewable energy sources. In the three last decades, the level of penetration of renewable energy sources has undergone an important growth in several countries, mainly in the USA and Europe, where levels of 20% have been reached. Main technologies of renewable energies include wind, hydraulic, solar (photovoltaic and thermal), biofuels (liquid biodiesel, biomass, biogas), and geothermal energy. Within this great variety of alternative energy sources, wind energy has experienced a fast growth due to several advantages, such as costs, feasibility, abundance of wind resources, maturity of the technology and shorter construction times (Ackermann, 2005). This trend is expected to be increased even more in the near future, sustained mainly by the cost competitiveness of wind power technology and the development of new power electronics technologies, new circuit topologies and control strategies (Guerrero et al., 2010). However, there are some disadvantages for wind energy, as wind generation is uncontrollably variable because of the intermittency of the primary resource, i.e. the wind. Another important disadvantage is that the best places to install a wind farm, due to the certainty and intensities of suitable wind, are located in remote areas. This aspect requires of additional infrastructure to convey the generated power to the demand centres. Unfortunately, in several countries the regulatory aspect does not follow this fast growth of wind possibilities. Many countries do not have specific rules for wind generators and others do not make the necessary operating studies before installing a wind farm (Heier, 2006). Power system operators must consider the availability of these power plants which are not dispatchable and are not accessible all the time. Today, developing countries, such as Argentina, are subjected to an analogous situation with wind energy, having perhaps one of the best sources of such energy around the world. Nowadays, there are several operative wind farms and others in stage of building and planning. Similar to other countries, in Argentina there is a lack of regulatory aspects related to this topic (Labriola, 2007). This chapter thoroughly presents a revision of wind generation, including the following sections. In the first part, a brief history of the wind energy developments is presented. Following, some remarks related to the modern wind energy systems are made. Then, a survey of modern structures of wind turbines is carried out, including towers and foundations, rotor, nacelle with drive train and other equipment, control systems, etc. Subsequently, major wind turbine concepts related to fixed and variable speed operation and control modes are described. Eventually, technical and regulatory exigencies for the integration of wind generation into the electrical grid are discussed in detail, including a study of selected countries grid codes.Fil: Molina, Marcelo Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; ArgentinaFil: Gimenez Alvarez, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Departamento de Ingeniería Electromecánica; Argentin

Instability onset for submerged cylinders

This paper describes how the global stability of a circular cylinder is affected when submerged in a two-phase gravitational flow. The flow behavior is governed by both the Reynolds and the Froude number, while the depth of the cylinder has been varied to create different scenarios for the stability analysis. The baseflow obtained by the numerical solution of the 2D Navier-Stokes equations has been analyzed, and the first bifurcation (i.e. Hopf type) has been explored for different depths, Reynolds and Froude numbers. In addition to the typical vortex shedding instabilities associated to isolated cylinders, the presence of an interface between fluids creates new instabilities associated with the free surface that present more complex and deformed structures. According to the region of the parameter space studied here, two main causes of instabilities have been found: the ones provoked by vortex shedding on the cylinder wake (wake instabilities) at low Froude numbers and the ones produced by the free surface deformation (free surface instabilities) at high Froude numbers. When instabilities are related to vortex shedding, the critical Reynolds number and the frequency of the most unstable mode are comparable to the classical solution without free surface and gravity effects. In all cases, the shape of the most unstable mode is deformed and distorted according to the free surface location, while the critical Reynolds numbers and the frequency associated to the perturbation are both affected by the gravity and the free surface presence.Fil: González-Gutierrez, Leo M.. Universidad Politécnica de Madrid; EspañaFil: Gimenez, Juan Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Ferrer, Esteban. Universidad Politécnica de Madrid; Españ

A Multiscale Approach for the Numerical Simulation of Turbulent Flows with Droplets

A multiscale approach for the detailed simulation of water droplets dispersed in a turbulent airflow is presented. The multiscale procedure combines a novel representative volume element (RVE) with the Pseudo Direct Numerical Simulation (P-DNS) method. The solution at the coarse-scale relies on a synthetic model, constructed using precomputed offline RVE simulations and an alternating digital tree, to characterize the non-linear dynamic response at the fine-scale. A set of numerical experiments for a wide range of volume fractions, particle distribution sizes, and external shear forces in the RVE are carried out. Quantitative results of the statistically stationary turbulent state are obtained, and the turbulence modulation phenomenon due to the presence of droplets is discussed. The developed synthetic model is then employed to solve global scale simulations of flows with airborne droplets via the P-DNS method. Improved predictions are obtained for flow conditions where turbulence modulation is noticeable.Fil: Gimenez, Juan Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Idelsohn, Sergio Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Oñate, Eugenio. Universidad Politécnica de Catalunya; EspañaFil: Löhner, Rainald. George Mason University; Estados Unido

A pseudo-DNS method for the simulation of incompressible fluid flows with instabilities at different scale

The final publication is available at Springer via http://dx.doi.org/10.1007/s40571-019-00264-xIn this work, a new model for the analysis of incompressible fluid flows with massive instabilities at different scales is presented. It relies on resolving all the instabilities at all scales without any additional model, i.e., following the direct numerical simulation style. Nevertheless, the computation is carried out at two levels or scales, termed the coarse and the fine. The fine-scale simulation is performed on representative volume elements providing the homogenized stress tensor as a function of several dimensionless numbers characterizing the flow. Consequently, the effect of the fine-scale instabilities is transferred to the coarse level as a homogenized stress tensor, a procedure inspired by standard multi-scale methods used in solids. The present proposal introduces a new way for the treatment of the flow at the fine scale, simulating not only the coarse scale but also the fine scale with all the necessary detail, but without incurring in the excessive computational cost of the classical DNS. Another interesting aspect of the present proposal is the use of a Lagrangian formulation for convecting the eddies simulated on the fine mesh through the coarse domain. Several examples showing the potentiality of this methodology for the simulation of homogeneous flows are presented.The authors express their most sincere gratitude to Xavier Oliver, Alfredo Huespe, and Pablo Sanchez for many fruitful discussions and valuable advises regarding the multi-scale methods. We sincerely thank Eugenio Oñate for continuous support and multiple suggestions for alleviating the problems faced in the development of the method.We also thank Pablo Becker for his trials which allowed us to obtain first unstable solutions on an RVE. Axel Larreteguy wishes to acknowledge the support from UADE and Banco Santander RIO through Grant BSR181. Juan Gimenez and Norberto Nigro wish to acknowledge CONICET, Universidad Nacional del Litoral (CAI+D 2016 PJ 50020150100018LI), and Agencia Nacional de Promoción Científica y Tecnológica (PICT 2016-2908).Peer ReviewedPostprint (author's final draft

A hybrid second-order method implemented in OpenFoam

Se presenta una nueva metodología Lagrangiana-Euleriana (LE) para la solución de problemas de flujo incompresible denominada Particle Finite Volume Method (PFVM). A diferencia de otros métodos LE que se encuentran en la literatura, la propuesta obtiene convergencia cuadrática global (en espacio y en tiempo) sobre mallas arbitrarias. PFVM consiste en utilizar un splitting simétrico de los operadores diferenciales en donde la convección se resuelve con una versión mejorada del método X-IVS, la difusión en una malla fija y se utilizan operadores de alto orden para transferir campos entre la malla y las partículas. La implementación en la plataforma open source OpenFOAM(R) permite emplear mallar arbitrarias de poliedros y realizar comparaciones de tiempo de cómputo contra los solvers estándar que provee dicha suite. Los casos evaluados revelan que PFVM obtiene menor error sin incrementar el costo computacional. Finalmente se presenta la extensión de la metodología incorporando un modelo de turbulencia pseudo-DNS. El modelo propone resolver el problema turbulento en el dominio de flujo original usando una malla relativamente gruesa, las partículas transportando las inestabilidades, y actualizando las tensiones turbulentas con datos precalculados a partir de simulaciones DNS locales.A novel hybrid Lagrangian-Eulerian (LE) methodology for flow problems, named Particle Finite Volume Method (PFVM), is presented. In contrast with other LE methods, this proposal obtains quadratic convergence in space and time over arbitrary meshes. PFVM uses a symmetrical splitting of operators, where the convection is solved with particles using an improved version of the X-IVS method, the diffusion on a fixed mesh, and high-order operators are employed to transfer fields between particles and grid. The implementation on the open-source platform OpenFOAM(R) allows employing arbitrary polyhedral meshes and comparing computing times against standard solvers of the suite. Results show that PFVM obtains lower error level without increasing the computing time. Finally, an extension of the methodology is presented, where a pseudo-DNS turbulence model is included. This approach solves the turbulent problem using a relatively coarse grid and updating the turbulent stresses with pre-computed data from local DNS simulations.Fil: Gimenez, Juan Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Aguerre, Horacio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Idelsohn, Sergio Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Nigro, Norberto Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaMECOM 2018 : XXII Argentinean Congress on Computational MechanicsSan Miguel de TucumánArgentinaAsociación Argentina de Mecánica ComputacionalUniversidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnologí

Desarrollo de una herramienta de diagnóstico enparalelo de calidad de mallas basada en OPENFOAM(R) para problemas de CFD

El presente documento presenta los lineamientos generales del desarrollo de una herramienta de diagnóstico de calidad de mallas orientada a problemas de CFD, que mediante la generación y posterior visualización de parámetros de calidad por celda a priori (aquellos referidos a la calidad geométrica de la malla utilizada) y a posteriori (aquellos obtenidos a partir de una solución del problema) suponen un aporte al usuario al obtener indicadores de como la geometría de la malla podría estar afectando a la solución obtenida. Trabajos posteriores podrían utilizar estos estimadores para realizar correcciones o refinamientos inteligentes en zonas clave de la malla.Publicado en: Mecánica Computacional vol. XXXV no.45Facultad de Ingenierí

Evaluación de la respuesta serológica contra IBR a partir de la utilización de vacunas polivalentes disponibles en el mercado

La Rinotraqueítis infecciosa bovina (IBR) es una enfermedad de distribución mundial que provoca grandes pérdidas económicas en nuestro país y el mundo. En la provincia de La Pampa se ha reportado su presencia y amplia distribución territorial. En general la prevención de IBR ha estado centrada en la utilización de vacunas polivalentes. El objetivo del presente trabajo fue evaluar la respuesta serológica a través de los niveles de anticuerpos presentes. Para ello se utilizaron 3 vacunas comerciales polivalentes que contenían en su formulación Herpesvirus bovino tipo 1 (BVH1) inactivado. Se utilizaron 4 grupos de terneros. G1 estuvo integrado por 14 animales, G2 y G3 por 13 animales y G4 o control (-) por 9 animales. Los animales fueron vacunados en dos oportunidades con un intervalo de 21 días. Para la detección de anticuerpos se utilizó un kit de ELISA. Al finalizar el ensayo al día 42 el porcentaje de animales que presentaron anticuerpos vacunales contra IBR fue del 42,8%, 61,5% y 38,4% para los grupos G1, G2 y G3 respectivamente y de 0% para los animales de G4 o grupo control (-). Las medias geométricas del IRPC (Índice Relativo x 100) en la misma fecha fueron de 16,31; 27,7 y 15,12 para los grupos G1, G2 y G3 respectivamente. Las vacunas utilizadas desarrollaron anticuerpos contra IBR en todos los grupos inoculados existiendo diferencias en el porcentaje de animales positivos de cada grupo. Los niveles de anticuerpos generados por las diferentes vacunas no presentaron diferencias significativas entre sí. Por último, se encontraron diferencias significativas entre el nivel de anticuerpos generado por las vacunas y los niveles obtenidos por pasaje viral.Infectious Bovine Rhinotracheitis (IBR) is a worldwidedisease which causes great economic losses in Argentina and around the world. Its presence and high prevalence 3have been reported in the province of La Pampa. IBR prevention strategy has mostly been focused on the use of polyvalent vaccines. The objective of our research was to evaluate the serological response, assessing antibodieslevels applyingthree polyvalent commercial vaccines containing inactivated bovine herpesvirus type 1 (BVH1). To that aim, four groups of calves were used: G1 consisted of 14 animals, G2 and G3 of13 animals,and negative controlconsistedof9 animals. The animals were vaccinated twice with an interval of 21 days. Antibodies levelswere measured by means of ELISA. At the end of the trial, the percentage of animals in each group that showed vaccinal antibodies against IBR were: 42.8%, 61.5% and 38.4% for G1, G2 and G3 respectively,and 0% for G4 or negativecontrolgroup. The geometric means of the IRPC (Relative Index x 100) on the same date were 16.31; 27.7 and 15.12 for groups G1, G2 and G3 respectively. The vaccines used,developed antibodies in all the inoculated groups, with differencesin the percentage of positive animalsin each group. The levels of antibodies generated by the different vaccines did not present significant differences between them. Finally, significant differences were found between the levels of antibodies generated by the vaccines and the levels obtained by viral passage.AER Victorica, INTAFil: Lux, Juan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil. Agencia de Extensión Rural Victorica; ArgentinaFil: Gimenez, Hugo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Torrado, Juan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil. Agencia de Extensión Rural Victorica; ArgentinaFil: Echeveste, Oscar. Escuela Provincial Agrotécnica “Florencio Peirone”. Victorica, La Pampa. ArgentinaFil: Fort, Marcelo Cristián. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; Argentin

SPINK7 expression changes accompanied by HER2, P53 and RB1 can be relevant in predicting oral squamous cell carcinoma at a molecular level

The oral squamous cell carcinoma (OSCC), which has a high morbidity rate, affects patients worldwide. Changes in SPINK7 in precancerous lesions could promote oncogenesis. Our aim was to evaluate SPINK7 as a potential molecular biomarker which predicts OSCC stages, compared to: HER2, TP53, RB1, NFKB and CYP4B1. This study used oral biopsies from three patient groups: dysplasia (n = 33), less invasive (n = 28) and highly invasive OSCC (n = 18). The control group consisted of clinically suspicious cases later to be confirmed as normal mucosa (n = 20). Gene levels of SPINK7, P53, RB, NFKB and CYP4B1 were quantified by qPCR. SPINK7 levels were correlated with a cohort of 330 patients from the TCGA. Also, SPINK7, HER2, TP53, and RB1, were evaluated by immunohistofluorescence. One-way Kruskal–Wallis test and Dunn's post-hoc with a p < 0.05 significance was used to analyze data. In OSCC, the SPINK7 expression had down regulated while P53, RB, NFKB and CYP4B1 had up regulated (p < 0.001). SPINK7 had also diminished in TCGA patients (p = 2.10e-6). In less invasive OSCC, SPINK7 and HER2 proteins had decreased while TP53 and RB1 had increased with respect to the other groups (p < 0.05). The changes of SPINK7 accompanied by HER2, P53 and RB1 can be used to classify the molecular stage of OSCC lesions allowing a diagnosis at molecular and histopathological levels.Fil: Pennacchiotti, Graciela Laura. Universidad de Chile; ChileFil: Valdes Garrido, Fabio. Instituto Nacional del Cáncer; ChileFil: González Arriaga, Wilfredo Alejandro. Universidad de Valparaíso; ChileFil: Montes, Héctor Federico. Universidad Nacional de Cuyo. Facultad de Odontologia; ArgentinaFil: Parra, Judith Maria Roxana. Universidad Nacional de Cuyo. Facultad de Odontologia; ArgentinaFil: Guida, Valeria Andrea. Universidad Nacional de Cuyo. Facultad de Odontologia; ArgentinaFil: Gomez, Silvina Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Guerrero Gimenez, Martin Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Fernandez Muñoz, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Zoppino, Felipe Carlos Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Caron, Ruben Walter. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Ezquer, Marcelo Eduardo. Universidad del Desarrollo; ChileFil: Ramires Fernández, Ricardo. Universidad Mayor; ChileFil: Bruna, Flavia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Odontologia; Argentin