In this thesis, an approach is presented for the generation of grids suitable for the simulation of high Reynolds number viscous flows in complex three-dimensional geometries. The automatic and reliable generation of such grids is today on the biggest bottlenecks in the industrial CFD simulation environment. In the proposed approach, unstructured tetrahedral grids are employed for the regions far from the viscous boundaries of the domain, while semi-structured layers of high aspect ratio prismatic and hexahedral elements are used to provide the necessary grid resolution inside the boundary layers and normal to the viscous walls. The definition of the domain model is based on the STEP ISO standard and the topological information contained in the model is used for applying the hierarchical grid generation parameters defined by the user. An efficient, high-quality and robust algorithm is presented for the generation of the unstructured simplicial (triangular of tetrahedral) part of the grid. The algorithm is based on the Delaunay triangulation and the internal grid points are created following a centroid or frontal approach. For the surface grid generation, a hybrid approach is also proposed similar to the volume. Semi-structured grids are generated on the surface grid (both on the edges and faces of the domain) to improve the grid resolution around convex and concave ridges and corners, by aligning the grid elements in the directions of high solution gradients along the surface. A method is also developed for automatically setting the grid generation parameters related to the surface grid generation based on the curvature of the surface in order to obtain an accurate and smooth surface grid. Finally, a semi-structured prismatic/hexahedral grid generation algorithm is presented for the generation of the part of grid close to the viscous walls of the domain. The algorithm is further extended with improvements meant to increase the grid quality around concave and convex ridges of the domain, where the semi-structured grids are known to be inadequate. The combined methodology is demonstrated on a variety of complex examples mainly from the automotive and aeronautical industry.

The agri-food industry is an important economic and social engine in many countries, not only because of its economic importance, but also because of its vital significance. For years, it has been possible to consider that this sector evolution has conducted to the development of centralized and global distribution networks. These global distribution networks, in a market of low value-for-weight products, are more efficient the more centralized their logistics be. This new paradigm has a collateral effect which is the difficult survival of the small producer-sellers with the problems that this entails for citizens as society members. This thesis is part of a project conducted by the Universitat Politècnica de València professors named as HOF3M (Heterarchical Open Food 3-sustainable Market). The project aims to facilitate the development of a triple bottom-line food product market, generating the technological and business bases to reduce entry barriers, so that anyone, anywhere in the world can become an agent that approaches any producer to any consumer. The aim of this thesis is to "provide a methodology for identifying and analysing business models through case studies, with the objective of creating a triple bottom-line, replicable and non-scalable business model bank in the agri-food industry". The application of this methodology provides a tool that facilitates the replicability of business models in the agri-food business context. In addition, it allows to identify those triply sustainable and non-scalable models that can be implemented by consumers, producers and intermediaries. The research work is carried out from literature reviews to understand the business models scope, triple bottom-line business and the context of the agri-food economy, as well as the application of the case study research methodology, for which the proposal is validated. This thesis gives three fundamental contributions: a methodology to identify and analyse a business model through study cases, a triple bottom-line assessment model within the agri-food economy framework, and three food retailing business model analysis. / El sector agroalimentario supone un importante motor económico y social en muchos países, no solo por su relevancia económica, sino también por su significado vital. Desde hace años se puede considerar que la evolución del sector ha derivado en el desarrollo de redes de distribución centralizadas y globales. Estas redes de distribución globales, en un mercado de productos de bajo ratio valor/peso, son más eficientes cuanto más centralizada esté su logística. Este nuevo paradigma tiene como efecto colateral la difícil pervivencia del pequeño productor-vendedor con los problemas que esto supone para el ciudadano en cuanto a miembro de la sociedad. Esta tesis se enmarca en un proyecto de profesores de la Universitat Politècnica de València denominado HOF3M (Heterarchical Open Food 3-sustainable Market). El proyecto tiene el objetivo de facilitar el desarrollo de un mercado triplemente sostenible de productos alimentarios, generando las bases tecnológicas y de negocio que reduzcan las barreras de entrada para que, cualquiera, en cualquier lugar del planeta pueda convertirse en un agente que acerque cualquier productor a cualquier consumidor. El objetivo de esta tesis se concreta en "proporcionar una metodología para la identificación y el análisis de modelos de negocio, a través del estudio de casos prácticos en empresas, con el objeto de confeccionar un banco de modelos de negocio triplemente sostenibles, replicables y no escalables en el sector agroalimentario". La aplicación de esta metodología proporciona una herramienta que facilita la replicabilidad de modelos de negocio en el tejido empresarial agroalimentario. Además, permite identificar aquellos modelos triplemente sostenibles y no escalables, que pueden ser implementados por consumidores, productores e intermediarios. El trabajo de investigación se realiza desde las revisiones de literatura para el entendimiento del ámbito de los modelos de negocio, de la triple sostenibilidad empresarial y del contexto de la economía agroalimentaria, además de la aplicación de la metodología de investigación a tres casos de estudio, con los cuales se valida la propuesta. De esta tesis se extraen tres aportaciones fundamentales: una metodología para identificar y analizar un modelo de negocio a través de casos de estudio, un modelo de evaluación de la triple sostenibilidad en el marco de la economía agroalimentaria, y tres análisis de modelos de negocio de venta al por menor de alimentos. / El sector agroalimentari suposa un important motor econòmic i social en molts països, no només per la seva rellevància econòmica, sinó també pel seu significat vital. Des de fa anys es pot considerar que l'evolució del sector ha derivat en el desenrotllament de xarxes de distribució centralitzades i globals. Estes xarxes de distribució globals, en un mercat de productes de baix ràtio valor/pes, són mes eficients quant mes centralitzada estiga la seua logística. Este nou paradigma té com a efecte col·lateral la difícil pervivència del xicotet productor-venedor amb els problemes que açò suposa per al ciutadà quant a membre de la societat. Esta tesi s'emmarca en un projecte de professors de la Universitat Politècnica de València denominat HOF3M (Heterarchical Open Food 3-sustainable Market). El projecte té l'objectiu de facilitar el desenrotllament d'un mercat triplement sostenible de productes alimentaris, generant les bases tecnològiques i de negoci que reduïsquen les barreres d'entrada perquè, qualsevol, en qualsevol lloc del planeta puga convertir-se en un agent que acoste qualsevol productor a qualsevol consumidor. L'objectiu d'esta tesi es concreta en "proporcionar una metodologia per a la identificació i l'anàlisi de models de negoci, a través de l'estudi de casos pràctics en empreses, amb l'objecte de confeccionar un banc de models de negoci triplement sostenibles, replicables i no escalables en el sector agroalimentari". L'aplicació d'esta metodologia proporciona una ferramenta que facilita la replicabilidad de models de negoci en el teixit empresarial agroalimentari. A més, permet identificar aquells models triplement sostenibles i no escalables, que poden ser implementats per consumidors, productor i intermediaris. El treball d'investigació es realitza des de les revisions de literatura per a l'enteniment de l'àmbit dels models de negoci, de la triple sostenibilitat empresarial i del context de l'economia agroalimentària, a més de l'aplicació de la metodologia d'investigació a tres casos d'estudi, amb els quals es valida la proposta. D'esta tesi s'extrauen tres aportacions fonamentals: una metodologia per a identificar i analitzar un model de negoci a través de casos d'estudi, un model d'avaluació de la triple sostenibilitat en el marc de l'economia agroalimentària, i tres anàlisis de models de negoci de venda al detall d'aliments. / Galeano Revert, AM. (2017). PROPUESTA DE METODOLOGIA PARA LA IDENTIFICACION Y EL ANALISIS DE MODELOS DE NEGOCIO TRIPLEMENTE SOSTENIBLES EN EL SECTOR AGROALIMENTARIO [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/88395 / TESIS

In this thesis, an approach is presented for the generation of grids suitable for the simulation of high Reynolds number viscous flows in complex three-dimensional geometries. The automatic and reliable generation of such grids is today on the biggest bottlenecks in the industrial CFD simulation environment.<p><p>In the proposed approach, unstructured tetrahedral grids are employed for the regions far from the viscous boundaries of the domain, while semi-structured layers of high aspect ratio prismatic and hexahedral elements are used to provide the necessary grid resolution inside the boundary layers and normal to the viscous walls. The definition of the domain model is based on the STEP ISO standard and the topological information contained in the model is used for applying the hierarchical grid generation parameters defined by the user. An efficient, high-quality and robust algorithm is presented for the generation of the unstructured simplicial (triangular of tetrahedral) part of the grid. The algorithm is based on the Delaunay triangulation and the internal grid points are created following a centroid or frontal approach. For the surface grid generation, a hybrid approach is also proposed similar to the volume.<p>Semi-structured grids are generated on the surface grid (both on the edges and faces of the domain) to improve the grid resolution around convex and concave ridges and corners, by aligning the grid elements in the directions of high solution gradients along the surface. A method is also developed for automatically setting the grid generation parameters related to the surface grid generation based on the curvature of the surface in order to obtain an accurate and smooth surface grid. Finally, a semi-structured prismatic/hexahedral grid generation algorithm is presented for the generation of the part of grid close to the viscous walls of the domain. The algorithm is further extended with improvements meant to increase the grid quality around concave and convex ridges of the domain, where the semi-structured grids are known to be inadequate.<p><p>The combined methodology is demonstrated on a variety of complex examples mainly from the automotive and aeronautical industry. / Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished