Luciano Garelli

National Scientific and Technical Research Council | conicet · Centro de Investigación de Métodos Computacionales

Nowadays, as an alternative to conventional mineral oils used for cooling in distribution transformers, environment-friendly ester oils are getting more attention. For this reason, the main objective of this work was to compare the cooling efficiency of both types of coolants in the medium-power distribution transformer under different ambient cond...

Se presenta una modelización numérica del flujo tridimensional de un fluido viscoso newtoniano en régimen oscilatorio alrededor de un microresonador de tipo placa utilizado en sistemas microelectromecánicos (MEMS). El microresonador consiste en una placa de oro con una alta relación de aspecto, de muy bajo espesor, perforada con 18 × 4 orificios cu...

Power transformers are the first devices used to transfer the electrical energy produced in power plants to the grid to supply the industrial and individual receivers with electricity. The heat generation in windings and core, being an effect of the power losses, is usually dissipated in large units by using mineral oils, which are harmful to the e...

In this work, a three-dimensional thermo-fluid dynamics simulation using the multiphysics code Code Saturne is carried out, in order to analyze the performance of delta-wing vortex generators for enhancing the heat exchange in panel type radiators. These radiators are widely used in electric power transformers. The study is focused on natural conve...

The aim of this paper is to reproduce the phenomenon of the intermediate axes theorem also known as the Dzhanibekov effect or the Tennis Racket effect. A RBD (Rigid Body Dynamic) model with 6DOFs (six degrees of freedom) was developed to reproduce the Euler's law of motion. Furthermore, in the RBD model, quaternions are employed for the mathematica...

The aim of this project is the identification of the drag coefficient (CD) in order to generate an aerodynamic description for a projectile flight dynamic. A Movil Horizon Estimation (MHE) algorithm that utilizes adaptive estimation methods to update the parameters of the arrival cost was applied to obtain a profit in the identification process. Bo...

This work describes the electromagnetic and coupled thermo-fluid dynamic analysis of an Oil-Natural Air-Natural (ONAN) distribution transformer with the main objective of studying the changes in the heat dissipation performance when the fluid employed to cool the machine is a biodegradable ester instead of mineral oil. The distribution transformer...

This work introduces a coupled electromagnetic, thermal and fluid flow analysis of an oil-natural air-natural distribution transformer in order to study the changes in the heat dissipation performance when a biodegradable ester is used to cool the device instead of mineral oil. The transformer has a rated power of 315kVA and a voltage ratio of 13.2...

Improving gas turbine performance depends almost exclusively on the maximum temperature of the combustion gases. This temperature is limited by the thermomechanical strength of the turbine vanes. In this work, a Chimera approach for overlapping grids in the finite element method (FEM) context is proposed to optimize the arrangement of several cooli...

Improving gas turbine performance depends almost exclusively on the maximum temperature of the combustion gases. This temperature is limited by the thermomechanical strength of the turbine vanes. In this work, a Chimera approach for overlapping grids in the finite element method (FEM) context is proposed to optimize the arrangement of several cooli...

A novel approach using an algebraic-based Chimera type domain composition method in the context of the finite element method for non-matching overlapping unstructured grids is proposed in this work. The scheme is based on both the transfer of information across each grid interface via Dirichlet boundary conditions and a high-order interpolation alg...

A novel approach using an algebraic-based Chimera type domain composition method in the context of the finite element method for non-matching overlapping unstructured grids is proposed in this work. The scheme is based on both the transfer of information across each grid interface via Dirichlet boundary conditions and a high-order interpolation alg...

In this paper, a three-dimensional numerical simulation is used to analyze the performance of delta-wing vortex generators for enhancing the heat exchange in panel type radiators, which are widely used in electric power transformers. The study is focused on natural convection and buoyancy-driven flows, which are common working conditions for this t...

The aim of this project is the identification of the aerodynamic coefficients in order to generate a complete aerodynamic description for a projectile flight dynamics. An efficient algorithm was developed to perform the estimation of the aerodynamic coefficients. Moreover, the complete trajectory is computed with an advanced coupled Computing Fluid...

La implementación del método chimera nos permite: Tratar con fronteras móviles con grandes desplazamientos o deformaciones, como sucede en problemas de Interacción Fluido-Estructura o problemas de Optimización. Prevenir la degradación de la calidad de la malla durante el movimiento de los bordes. Dividir el proceso de generación de la malla en el m...

En este trabajo de investigación se lleva a cabo una simulación numérica tridimensional con el objetivo de analizar el rendimiento del generador de vórtice tipo ala delta para mejorar el intercambio de calor en los radiadores tipo panel. El estudio se centra en flujos con convección natural e impulsados por flotación, siendo esta una situación cara...

In this work Valgrind's Tool Suite is used to profile memory usage (Cachegrind) and to graph function calls (Callgrind) when running Code Saturne with OpenMP. The object of this analysis is to detect possible code's bottlenecks in order to improve performance in shared memory environments. Finally, the code is compiled using Profile-Guided Optimiza...

A key point in heat transfer in ducts and heat exchangers in general is that the efficiency in the heat transfer from the oil to the air is basically limited by the thermal resistance in the adjacent boundary layer as the air raises in the channel between two fins.One way of enhancing the heat transfer is to promote a secondary flow that transports...

Investigación numérica del efecto de deflectores sobre el rendimiento de una turbina de eje vertical. Determinación de la geometría y ubicación óptima de los deflectores para mejorar la eficiencia de la turbina construida. Desarrollo de una metodología de optimización basada en gradientes acoplada con un metamodelo de redes neuronales.

El objetivo de este trabajo es realizar la optimización geométrica de los deflectores de aire para una turbina eólica de eje vertical (VAWT) impulsada por arrastre (drag) tipo Savonius. El torque generado por este tipo de turbinas resulta de la diferencia entre las fuerzas de arrastre generado por las geometrías concavas y convexas de los álabes, r...

Palabras Clave: generadores de vórtices, transferencia de calor, radiadores de transformadores eléctricos. Resumen. El rendimiento de los intercambiadores de calor es un factor clave en muchas aplicaciones industria-les, como en el acondicionamiento de aire, en la ingeniería química y en transformadores eléctricos de potencia, entre otras. Mejorar...

The need of ensuring the trajectory of a projectile so as to achieve a target has always been a challenge for exterior ballistic engineers. One of the most suitable techniques consists in simulate the projectile at different angles of attack with Computational Fluid Dynamic (CFD) software to obtain the corresponding aerodynamic coefficients. This p...

Palabras Clave: Transformador de potencia, Dinámica de fluidos computacional, Transferen-cia de calor. Resumen. En este artículo se presenta un estudio termo-fluido dinámico sobre un transformador de potencia de 30MVA. El estudio incluye cálculos semi-analíticos, simulaciones numéricas y mediciones experimenta-les para validar los resultados obteni...

This paper presents semi-analytical calculations, computational fluid dynamic simulations and experimental measurements accomplished on a typical 30MVA power transformer. An ad-hoc workbench was devised to carry out the experimental measurements. This facility allowed to estimate the values of different key variables involved in heat dissipation wi...

This research work evaluates the performance of a Fluid Structure Interaction (FSI) solver, which is created using a generic interface to couple two independent software packages. The basic idea is to combine the advantages of the two independent codes to create a powerful FSI solver for two and three dimensional FSI analysis using the concept of m...

This research work evaluates the performance of a Fluid-Structure Interaction (FSI) solver, which is created using a generic interface to couple two independent software packages. The basic idea is to combine the advantages of the two independent codes to create a powerful FSI solver for two and three dimensional FSI analysis using the concept of m...

A Navier-Stokes solver based on Cartesian structured finite volume discretization with embedded bodies is presented. Fluid structure interaction with solid bodies is performed with an explicit partitioned strategy. The Navier-Stokes equations are solved in the whole domain via a Semi-Implicit Method for Pressure Linked Equations (SIMPLE) using a co...

There are Fluid-Structure Interaction (FSI) problems which require to use high performance computing resources through specialized parallel codes in order to deal with their numerical solution. Also, the computational effort involved in the solution of the fluid flow equations can be several orders of magnitude higher than that required to solve th...

This work is a first step in the understanding of the interaction process between internal shock waves and the flow transition inside of a rocket nozzle that develops during the engine start-up phase or when the nozzle is operated at over-expanded conditions. In many cases, this transition in the flow pattern produces side loads in the nozzle due t...

This paper discuss a coupling strategy of two different software packages to provide fluid structure interaction (FSI) analysis. The basic idea is to combine the advantages of the two codes to create a powerful FSI solver for two and three dimensional analysis. The fluid part is computed by a program called PETSc-FEM a software developed at Centro...

Abstract. Glaucoma is the optic nerve damage often associated with an increased intraocular pressure that leads to progressive and irreversible loss of vision. The Ahmed valve is a passive device constructed from two opposed deformable silicone elastomers sheets, commonly used for the regulation of intraocular pressure in patients with glaucoma. I...

This Report discuss a coupling strategy of two different software packages to provide fluid structure interaction (FSI) analysis. The basic idea is to combine the advantages of the two codes to create a powerful FSI solver for two and three dimensional analysis. The fluid part is computed by a program called PETSc-FEM a software developed at Centro...

Multidisciplinary and Multiphysics coupled problems represent nowadays a chal-lenging field when studying or analyzing even more complex phenomena that appear in nature and in new technologies (e.g. Magneto-Hydrodynamics, Micro-Electro-Mechanics, Thermo-Mechanics, Fluid-Structure Interaction, etc.). Particularly, when dealing with Fluid-Structure I...

In this article, a new methodology for developing discrete geometric conservation law (DGCL) compliant formulations is presented. It is carried out in the context of the finite element method for general advective–diffusive systems on moving domains using an ALE scheme. There is an extensive literature about the impact of DGCL compliance on the sta...

Las válvulas para el tratamiento de glaucoma son dispositivos que permiten disminuir la presión intraocular en pacientes con glaucomas refractarios a los tratamientos farmacológicos. En este trabajo se presenta un modelo que permite probar y analizar el desempeño de distintos dispositivos cuando son implantados en el ojo humano, en tiempo de diseño...

Glaucoma Drainage Device (GDD) have the potential to eliminate hypotony but still suffer from poor flow control and fibrosis. The ideal shunt should change its hydraulic resistance to achieve the desired intraocular pressure. In this work the characterization of a preliminary design of a new GDD is presented. This is activated by means of a diaphra...

Glaucoma drainage device (GDD) has the potential to eliminate hypotony but still suffers from poor flow control and fibrosis. The ideal shunt should change its hydraulic resistance to achieve the desired intraocular pressure (IOP). In this study, the characterisation of a preliminary design of a new GDD is presented. This is activated by means of a...

Generally, in problems where the Riemann invariants (RI) are known (e.g. the flow in a shallow rectangular channel, the isentropic gas flow equations), the imposition of non-reflective boundary conditions is straightforward. In problems where Riemann invariants are unknown (e.g. the flow in non-rectangular channels, the stratified 2D shallow water...

The aim of this paper is to analyze the aeroelastic processes developed during the starting phase of a rocket engine via a coupling fluid/structure code. This analysis gives a better understanding of the behavior of the structure as the shock waves propagate inside the engine nozzle. The gasdynamics Euler equations are solved for the fluid and cons...

The aim of this paper is to analyze the aeroelastic processes developed during the starting phase of a rocket engine via a coupling fluid/structure code. This analysis gives a better understanding of the behavior of the structure as the shock waves propagate inside the engine nozzle. The gasdynamics Euler equations are solved for the fluid and cons...

Resumen. En este trabajo se presentan resultados obtenidos a partir de la simulación y del análisis de explo-siones en recintos cerrados. Estas pueden ser originadas por la ignición de una mezcla de gases acumulados en un recinto, como en el caso de los hornos de destilación utilizados en la industria petroquímica, o provocadas por materiales explo...