Papers by Francesc Xavier Grau Vidal
World, 2025
Knowledge-based regional development policies have become increasingly popular in recent decades ... more Knowledge-based regional development policies have become increasingly popular in recent decades and have been widely disseminated and applied. The regional scale and regional policy have been no exception to this general trend, resulting in the coining of new terms, such as the knowledge region (KR). The use of this term has, however, suffered the consequences of a lack of consensus over its meaning. This has proven problematic and resulted in the term being applied in different ways according to the territorial context. To address this problem, the present study offers a definition of the term that identifies the main components of these different regional realities and provides examples of its appropriate use based on good practices. This new contribution has been based on the PRISMA methodology. The results highlight the existence of key components and the need for a governance framework that serves as a fundamental pillar of knowledgebased regional development. This study concludes with a proposal for a definition of the knowledge region that could be used as a model and basis for future research in this field.
This contribution analyzes the evolution of the higher education and doctorate in Europe and Spai... more This contribution analyzes the evolution of the higher education and doctorate in Europe and Spain in the last decades, and its relationship with the evolution of the economy based on knowledge. It also analyzes the strong impact that doctorate has on the research activity and the tensions between the Bologna process, that is collaborative, harmonious and open, and the productive economy based on research, which is dynamic and competitive. 22 Francesc Xavier Grau Vidal
Higher Education in the World 6. Towards a Socially Responsible University: Balancing the Global with the Local
The study of the dual responsibilities of universities at local and global level has been the obj... more The study of the dual responsibilities of universities at local and global level has been the objective of this 6th HEIW GUNI Report on “Towards a Socially Responsible Higher Education Institution; globally and locally engaged”. In this final chapter, the editorial team makes a joint reflection from all the contributions and give a set of recommendations for academia, academic leaders and Higher Education and Research policy-makers.
More than 80 experts from around the World have contributed to dissecting the topic and by identifying good practices that can help academic leaders and policy makers achieve the highest purposes of education and research. The contributions follow the initial structure of the Report of nine chapters with each of them being independent and standing on its own, offering a rich panorama of analysis, conclusions and recommendations. The reader is invited to go to these original articles for a deeper analysis on each of the topics. The final chapter of the Report is based on these contributions and has the purpose of providing a common and coherent set of general conclusions that propose directions of change or action for HE institutions and systems, to help them in developing as locally and globally engaged.
As a final remark, the diversity of responses to the dual demands for universities’ engagement are not only perfectly compatible; they must also be adopted simultaneously. This may be the biggest challenge of all: universities – particularly those specializing in research – must at the same time be recognized as civic, entrepreneurial, innovative, flagship, globally competitive and both locally and globally engaged. And HE&R policy makers have to design the appropriate environment of policies, public and private resources, data collection and accounting procedures, and public information to make it possible.
Higher Education in the World 6. Towards a Socially Responsible University: Balancing the Global with the Local
Towards a Socially Responsible University: Balancing the Global with the Local aims to analyse th... more Towards a Socially Responsible University: Balancing the Global with the Local aims to analyse the dual responsibilities of universities at local and global level, exploring the potential conflicts and intrinsic difficulties in addressing both the local demands of society based on the race for global competitiveness and the local and global demands to contribute to a more equitable and sustainable society (at local and global levels).
There is a dual perspective on global affairs: on one side, competition between national and regional economic systems when developing their respective societies still predominates, and on the other, there is the global sustainability of the sum of all these developments, which is gaining momentum. Higher education institutions (HEIs) can be identified as key players from both perspectives and, thus, have the singular responsibility of helping to provide appropriate and adequate responses to both legitimate needs and interests: i) to address the global challenges of the world, which are very well summarized by the UN Sustainable Development Goals (SDGs), and ii) to contribute to the social, cultural and economic development and international development of their societies. The current organization of higher education in the world urges universities to compete on the global stage for students, faculty and research contracts. At the same time, they are expected to contribute to the economic development of their localities and to sustainable and inclusive global and local development.
From this perspective, it becomes necessary to make the dual engagement of universities explicit: with the immediate needs of our local societies and with the global challenges of the world, of our global society. The study of this duality has been the objective of this 6th Higher Education in the World (HEIW) GUNi Report, ‘Towards a Socially Responsible University: Balancing the Global with the Local’.
El gobierno de las universidades. Reformas necesarias y tópicos manidos, 2015
Este artículo recoge y desarrolla la aportación del autor al curso “El gobierno de las universida... more Este artículo recoge y desarrolla la aportación del autor al curso “El gobierno de las universidades”, organizado por la Cátedra INCREA de la Universitat Jaume I, en Benicàssim en Julio de 2014, a partir de un texto propio “La Autonomía Universitaria y el Sistema de Gobernanza”, editado en 2013 por Publicacions URV. El presente texto argumenta la necesidad de una reforma del sistema de gobernanza a partir de las funciones estratégicas que en la actualidad desarrollan las universidades en los respectivos sistemas socio-económicos que las justifican y sustentan. El punto de partida para diseñar un sistema de gobernanza debería ser precisamente la identificación de la función que debe cumplir, lo que remite a la propia funcionalidad de la autonomía universitaria. La institución universitaria debe garantizar, por el bien de la sociedad, que, al generar y transmitir conocimiento, su actuación no responde a intereses grupales de ningún tipo. Constituye un servicio público que debe actuar con autonomía, y esa actuación incluye todos los mecanismos de toma de decisiones, esto es, el sistema de gobernanza en su conjunto que, desde esta perspectiva, se configura como el garante de la prestación del servicio público de educación superior e investigación con la máxima eficiencia, al tiempo que libre de la influencia de intereses políticos económicos o religiosos.
A partir de las conclusiones del estudio University Autonomy in Europe II. The Scorecard y de la actual situación del sistema universitario, de investigación y de innovación, el autor propone un conjunto concreto de elementos de gobernanza que abarcan todas las dimensiones de la autonomía universitaria.
This paper deals with the dual responsibilities of universities at local and global scale, explor... more This paper deals with the dual responsibilities of universities at local and global scale, exploring the potential conflict, or intrinsic difficulties, in addressing both local demands of society based on the race for global competitiveness and local and global demands to contribute to a more equitable and sustainable society (at local and global scales). Like many other organisations today, universities are under intense pressure, coming especially from 'local' demands. The paper analyses and proposes the elements that allow for the global and local engagement of universities. The vision of a university as a 'social force for good' makes engagement compatible with the immediate needs of local societies and the global challenges of the world. This is the real challenge of many universities all over the world that may be able to take on the responsibility of being a glocal university.
International Journal of Heat and Mass Transfer, 1999
A three!dimensional numerical study of the natural convection in a cubical cavity heated from bel... more A three!dimensional numerical study of the natural convection in a cubical cavity heated from below is reported at moderate Rayleigh numbers for three Prandtl numbers Pr 9[60\ 09 and 029[ The six walls are considered rigid and immobile\ with isothermal horizontal plates and adiabatic lateral walls[ The Boussinesq approximation for the variation of physical properties is assumed[ Seven di}erent structures\ four single roll!type\ two four roll!type and a toroidal roll\ and several~ow transitions have been identi_ed in the steady and laminar regime for Ra ¾ 5×09 3 and Pr ¾ 029[ Both\ the dynamic and heat transfer characteristics of these seven structures are discussed[ The e}ects of slightly changing the aspect ratio or tilting the cavity on the stability of the di}erent structures are also analyzed[ There is general agreement between the predicted average Nusselt number and available correlations for RayleighÐBe nard convection in rectangular enclosures and between two horizontal plates[ Þ 0887 Elsevier Science Ltd[ All rights reserved[
Computers & Fluids, 2010
In this paper, we analyze the influence of aiding and opposing buoyancy on the statistics of the ... more In this paper, we analyze the influence of aiding and opposing buoyancy on the statistics of the wall transfer rates in a mixed convection turbulent flow at low Reynolds numbers in a vertical plane channel. The analysis is carried out using a database obtained from direct numerical simulations performed with a second-order finite volume code. The aiding/opposing buoyancy produces an overall decrease/increase of the intensities of the fluctuations of the wall shear stresses in comparison with the forced convection flow. The near wall structures responsible for the positive extreme values of the fluctuations of the wall shear stress, educed by a conditional sampling technique, consist in two quasi-parallel counterrotating streamwise vortices that convect high momentum fluid towards the wall in the region between them. Buoyancy produces an overall increase of the Reynolds stresses near the cold wall in comparison with the hot wall. This affects the streamwise length, the orientation, the velocity and the intensity of these flow structures near the two walls of the channel. It is found that the flow structures near the cold wall are shorter and produce more intense fluctuations than those near the hot wall.
Computers & Fluids, 2007
In this paper we analyze the flow structures responsible for large local instantaneous deviations... more In this paper we analyze the flow structures responsible for large local instantaneous deviations of the conventional momentum-heat transfer analogy and large fluctuations of the wall shear stress and the wall heat flux in a forced convection turbulent channel flow at low-Reynolds numbers (Re = 4570, Pr = 0.7). The analysis was carried out using a database obtained from a direct numerical simulation performed with a second-order finite volume code. The ensemble averaged velocity and temperature profiles and profiles of the turbulence intensities and turbulent heat fluxes agree well with direct numerical simulations available in the literature. When the flow was statistically fully developed, we recorded the time evolution of the velocities and temperatures near one wall of the channel. The near wall structures responsible for the extreme values of the deviations were educed by a conditional sampling technique. Results show that extreme values of the wall shear stress and wall heat transfer rates, as well as departures from the conventional analogy between momentum and heat transfer, occur within the high-speed streaks on the wall and are associated with fluctuations of the streamwise pressure gradient. These large fluctuations on the wall are produced by the combined effect of two quasi-parallel counterrotating streamwise vortices.
International Journal of Heat and Mass Transfer, 2010
Using a typical shear cell arrangement, the degree of accuracy attained in the determination of t... more Using a typical shear cell arrangement, the degree of accuracy attained in the determination of the interdiffusion coefficients at low and moderate thermal and solutal Rayleigh numbers is analyzed here. It is concluded that, despite the marked directionality of these Fickian processes, thermal convective contamination is always negligible in real experiments but solutal convective contamination can be important even for moderate values of the solutal Rayleigh number. Nevertheless, in the range of values investigated and due to the above-mentioned directionality, the solutal convection could be minimized orienting the cell in such a way that its axis remains constantly aligned with the direction of the external disturbance.
International Journal of Heat and Mass Transfer, 2007
Experimental measurements and numerical simulations of natural convection in a cubical cavity hea... more Experimental measurements and numerical simulations of natural convection in a cubical cavity heated from below and cooled from above are reported at turbulent Rayleigh numbers using water as a convective fluid (Pr = 6.0). Direct numerical simulations were carried out considering the Boussinesq approximation with a second-order finite volume code (10 7 6 Ra 6 10 8 ). The particle image velocimetry technique was used to measure the velocity field at Ra = 10 7 , Ra = 7 Â 10 7 and Ra = 10 8 and there was general agreement between the predicted time averaged local velocities and those experimentally measured if the heat conduction through the sidewalls was considered in the simulations.
Experiments in Fluids, 2001
Rayleigh-Bénard convection in a cubical cavity with adiabatic or conductive sidewalls is experime... more Rayleigh-Bénard convection in a cubical cavity with adiabatic or conductive sidewalls is experimentally analyzed at moderate Rayleigh numbers (Ra ≤ 8 × 104) using silicone oil (Pr=130) as the convecting fluid. Under these conditions the flow is steady and laminar. Three single-roll-type structures and an unstable toroidal roll have been observed inside the cavity with nearly adiabatic sidewalls. The sequence from the conductive state consists of a toroidal roll that evolves to a diagonally oriented single roll with increasing Rayleigh number. This diagonal roll, which is stabilized by the effect of the small but finite conductivity of the walls, shifts its axis of rotation towards to two opposite walls, and back to the diagonal orientation to allow for the increase in circulation that occurs as the Rayleigh number is further increased. Conduction at the sidewalls modifies this sequence in the sense that the two initial single rolls finally evolve into a four-roll structure. Once formed, this four-roll structure remains stable when decreasing the Rayleigh number until the initial single diagonally oriented roll is again recovered. The topology and the velocity fields of all structures, characterized with visualization and particle image velocimetry, respectively, are in good agreement with numerical results reported previously for the cavity with adiabatic walls, as well as with the numerical predictions obtained in the present study for perfectly conducting lateral walls.
Physics of Fluids, 2005
This paper presents and discusses numerical simulations of forced convection heat transfer in a r... more This paper presents and discusses numerical simulations of forced convection heat transfer in a rotating square duct at high rotation rates. The mean pressure gradient has been kept constant in the simulations that were conducted with a second order finite volume code with a dynamical localized subgrid scale model. The rotation number based on the bulk velocity ͑Ro= 2⍀D / Ū b ͒ was varied from 0.12 to 6.6 and consequently the Reynolds number ͑Re= Ū b D / ͒ ranged from 3900 to 1810 according to the fact that rotation tends to increase the pressure drop in the duct. A model for estimating the velocities and the corresponding friction coefficient has been developed by analytically solving simplified versions of the momentum budgets within the Ekman layers occurring near the opposite two walls of the duct perpendicular to the rotation axis. The model reproduces accurately the velocity profiles of the numerical simulation at high rotation rates and predicts that the boundary layer quantities scale as Ek 1/2 ͑Ek= / ⍀D 2 ͒. At RoϾ 1 the Ekman layers are responsible for most of the pressure drop of the flow while the maximum heat transfer rates are found on the wall where the stratification of the x-momentum is unstable with respect to the Coriolis force. Rotation enhances the differences between the contributions of the local friction coefficients and local Nusselt numbers of the four walls of the duct and considerably increases, in comparison with the non-rotating case, the pressure drop of the flow and the Nusselt number. The overall friction coefficient of the measurements and the simulations existing in the literature, as well as the present numerical predictions, are well correlated with the equation 1.09͑Cf/ Ek 1/2 ͒ 1.25 = Ro in the range Roജ 1 for Reഛ 10 4 .
International Journal of Heat and Mass Transfer, 2010
We analyzed a database of a direct numerical simulation of natural convection in a vertical chann... more We analyzed a database of a direct numerical simulation of natural convection in a vertical channel. The flow is driven by a constant temperature difference imposed at the walls (Ra = 5.4 Â 10 5 , Pr = 0.7). The averaged flow and turbulent statistics are in good agreement with previous direct numerical simulations reported in the literature. Contrary to forced convection flows, the fluctuations of the heat transfer rate are uncorrelated with the fluctuations of the wall shear stress, which exhibit a symmetric probability density function. At the low Rayleigh number considered, the large-scale structures, which consist mainly in two counter-rotating vortices, with sizes comparable to the separation of the walls, are responsible for the extreme fluctuations of the wall heat transfer rate. The occurrence and the averaged topology of these structures have been determined using a conditional sampling technique.
Scaling of Transient Natural Convection Cooling in a Side-Cooled Cavity: The Effect of Variable Viscosity
ASME/JSME 2011 8th Thermal Engineering Joint Conference, 2011
ABSTRACT Export Date: 4 April 2013, Source: Scopus
Chemical Engineering Science, 2012
Numerical simulations of the two-phase flow distribution in a trickle-bed reactor used for fuel h... more Numerical simulations of the two-phase flow distribution in a trickle-bed reactor used for fuel hydrodesulfurization are reported. As a first step, the heat and mass transfer, as well as the chemical reactions, are not considered. The reactor has four packed-beds and a distribution tray above the catalytic beds equipped with cylindrical chimneys. The flow distribution at the outlet of the circular chimney predicted by the simulations is not axisymmetric because of the spatial distributions of the liquid and gas inlets in the chimney. This causes that the liquid entering the packed beds is distributed in three main streams. For the simulation of the two-phase flow in the packed beds, an Eulerian three-phase model that considers the particles of catalyst as a granular static phase has been used following the Holub single slit model for particle-fluid interaction to compute the liquid-solid and gas-solid drag coefficients. Numerical simulations of the dispersion of water-air flow in a column of glass beads using this model were initially carried out and results were found to be in reasonable agreement with numerical and experimental data available in the literature. The simulations consider the flow dispersion in the central region of the reactor bed as well as in the region close to the cylindrical lateral wall of the reactor. In both cases most of the liquid spreading takes place in the top part of the bed. The distributions of the liquid volume fraction do not change significatively as the depth of the bed is increased except in the third bed and at the interface of two beds with different porosity.
Experiments in Fluids, 2001
The authors would like to acknowledge the ®nancial support received from DGICYT projects no. PB93... more The authors would like to acknowledge the ®nancial support received from DGICYT projects no. PB93-0656-C02-01 and PB96-1011. One of the authors (J. P.) would like to thank the support received from the Cray Research Center in Eagan, Minn., to carry out several calculations on Cray supercomputers.
International Journal of Heat and Mass Transfer, 2010
We analyze numerical simulations of a second-order chemical reaction (Da = 1) in a fully develope... more We analyze numerical simulations of a second-order chemical reaction (Da = 1) in a fully developed turbulent plane channel flow at a low Reynolds number (Re s = 180). The reactive plume is formed when a reactant A is released through a line source into the channel flow doped with reactant B. Two different inlet pre-mixing conditions and line source heights are considered. Direct Numerical Simulations (DNS) and Stochastic Fields (SF) methods have been used and compared for these different conditions. The results obtained using SF are sensitive to the particular value of the turbulent Schmidt number (Sc T ) selected to model the turbulent dispersion. It has been found that if a representative value of Sc T extracted from DNS is used in the SF method, both DNS and SF, give similar results.
International Journal of Heat and Mass Transfer, 1996
Natural convection in a cubical cavity heated from below is examined by means of the threedimensi... more Natural convection in a cubical cavity heated from below is examined by means of the threedimensional computation of the time dependent Navier-Stokes and energy transport equations in the range of Rayleigh numbers 3500 $ Ra < 10000. The Boussinesq approximation has been used to model buoyancy effects on momentum transfer. Four different stable convective structures occur with orientation and flow circulation dictated by the combined effect of the four adiabatic confining lateral walls. Three of these structures are typical single rolls with their axis of rotation or vorticity horizontal and either parallel to two opposite vertical walls, structures Sl and S3, or orientated towards two opposite vertical edges (S2). The fourth structure (S4) is a nearly toroidal roll with the descending motion aligned with the four vertical edges and the single ascending current along the vertical axis of the enclosure. The effect of the Rayleigh number and the type of flow structure on heat transfer rates at the top and bottom plates is also reported. For the single roll-type structures the surface averaged Nusselt number increases with a power of the Rayleigh number that changes within the range studied from 0.7 to 0.4. A similar trend is observed for the toroidal roll but in this case heat transfer rates are 65% lower. The distribution of local heat transfer coefficients at the top and bottom surfaces agrees with the topology of the flow patterns portrayed with the aid of the second invariant of the velocity gradient and the modulus of the cross product of the corresponding velocity and vorticity fields.
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Papers by Francesc Xavier Grau Vidal
More than 80 experts from around the World have contributed to dissecting the topic and by identifying good practices that can help academic leaders and policy makers achieve the highest purposes of education and research. The contributions follow the initial structure of the Report of nine chapters with each of them being independent and standing on its own, offering a rich panorama of analysis, conclusions and recommendations. The reader is invited to go to these original articles for a deeper analysis on each of the topics. The final chapter of the Report is based on these contributions and has the purpose of providing a common and coherent set of general conclusions that propose directions of change or action for HE institutions and systems, to help them in developing as locally and globally engaged.
As a final remark, the diversity of responses to the dual demands for universities’ engagement are not only perfectly compatible; they must also be adopted simultaneously. This may be the biggest challenge of all: universities – particularly those specializing in research – must at the same time be recognized as civic, entrepreneurial, innovative, flagship, globally competitive and both locally and globally engaged. And HE&R policy makers have to design the appropriate environment of policies, public and private resources, data collection and accounting procedures, and public information to make it possible.
There is a dual perspective on global affairs: on one side, competition between national and regional economic systems when developing their respective societies still predominates, and on the other, there is the global sustainability of the sum of all these developments, which is gaining momentum. Higher education institutions (HEIs) can be identified as key players from both perspectives and, thus, have the singular responsibility of helping to provide appropriate and adequate responses to both legitimate needs and interests: i) to address the global challenges of the world, which are very well summarized by the UN Sustainable Development Goals (SDGs), and ii) to contribute to the social, cultural and economic development and international development of their societies. The current organization of higher education in the world urges universities to compete on the global stage for students, faculty and research contracts. At the same time, they are expected to contribute to the economic development of their localities and to sustainable and inclusive global and local development.
From this perspective, it becomes necessary to make the dual engagement of universities explicit: with the immediate needs of our local societies and with the global challenges of the world, of our global society. The study of this duality has been the objective of this 6th Higher Education in the World (HEIW) GUNi Report, ‘Towards a Socially Responsible University: Balancing the Global with the Local’.
A partir de las conclusiones del estudio University Autonomy in Europe II. The Scorecard y de la actual situación del sistema universitario, de investigación y de innovación, el autor propone un conjunto concreto de elementos de gobernanza que abarcan todas las dimensiones de la autonomía universitaria.