Métodos para aliviar las cargas de succión debidas a torbellinos cónicos en cubiertas y tejados

En esta comunicación se analiza la eficacia de parapetos verticales porosos y parapetos en voladizo para reducir la carga aerodinámica que el viento produce en las cubiertas de edificios de baja altura. Para ello se ha estudiado la influencia de los parámetros dependientes de los parapetos (porosidad, altura, longitud de los voladizos) en las cargas aerodinámicas que aparece sobre las cubiertas. Se ha encontrando que, dependiendo de los valores de esos parámetros, los diversos tipos de parapetos, excepto los muy porosos, pueden reducir de forma muy significativa la carga de viento sobre las cubiertas. El estudio ha sido llevado a cabo mediante ensayos en túnel aerodinámico, midiendo el coeficiente de presión en la cubierta de distintos tipos de modelos de ensayos, con el fin de determinar el modo en que los parapetos ensayados afectan a los torbellinos cónicos que aparecen en las cubiertas de las edificaciones, que son los responsables de la elevadas cargas de succión que puede darse en las cubiertas de edificios. Aunque el estudio sistemático de configuraciones de parapetos ha estado limitado al caso de cubiertas planas, también se presentan resultados medidos sobre modelos específicos de edificaciones con cubiertas no planas

Airfoil catalogue for wind turbine blades with OpenFOAM

A methodology to efficiently simulate wind tunnel tests of several airfoils with OpenFOAM has been developed in this work. This methodology bridges OpenFOAM capabilities with Matlab postprocessing to analyse efficiently the performance of wind turbine airfoils at any angle of attack. This technique has been developed to reduce the cost, in terms of time and resources, of wind tunnel campaigns on wind turbine blade airfoils. Different turbulence models were used to study the behaviour of the airfoils near stall. Wind turbine airfoils need to be characterized for all possible angles of attack, in order to reproduce the real aerodynamic patterns during operation. Unfortunately, this situation is translated into a huge demand of wind tunnel testing resources, airfoil manufacturing and data post-processing. The high costs in terms of experimental measurements have encouraged many researches to elaborate airfoil catalogues by performing CFD simulations.Results are compared with a testing campaign on wind turbine airfoils aerodynamics run at AB6 wind tunnel of IDR/UPM located at the campus Universidad Politécnica de Madrid (Madrid, Spain), this tunnel being particularly suited for bi-dimensional applications. It is an open wind tunnel with a test section of 2.5 x 0.5 m, the turbulence intensity is under 3% at a Reynolds number of Re ∼= 5×105. The central part of the airfoil mock-ups were built with a 3D printer Additive Fused Deposition Modelling technology (FDM). Simulation results show a fair agreement with experiments, and helped to improve the performance of the wind tunnel

Airfoil catalogue for wind turbine blades with OpenFOAM

A methodology to efficiently simulate wind tunnel tests of several airfoils with OpenFOAM has been developed in this work. This methodology bridges OpenFOAM capabilities with Matlab postprocessing to analyse efficiently the performance of wind turbine airfoils at any angle of attack. This technique has been developed to reduce the cost, in terms of time and resources, of wind tunnel campaigns on wind turbine blade airfoils. Different turbulence models were used to study the behaviour of the airfoils near stall. Wind turbine airfoils need to be characterized for all possible angles of attack, in order to reproduce the real aerodynamic patterns during operation. Unfortunately, this situation is translated into a huge demand of wind tunnel testing resources, airfoil manufacturing and data post-processing. The high costs in terms of experimental measurements have encouraged many researches to elaborate airfoil catalogues by performing CFD simulations.Results are compared with a testing campaign on wind turbine airfoils aerodynamics run at AB6 wind tunnel of IDR/UPM located at the campus Universidad Politécnica de Madrid (Madrid, Spain), this tunnel being particularly suited for bi-dimensional applications. It is an open wind tunnel with a test section of 2.5 x 0.5 m, the turbulence intensity is under 3% at a Reynolds number of Re ∼= 5×105. The central part of the airfoil mock-ups were built with a 3D printer Additive Fused Deposition Modelling technology (FDM). Simulation results show a fair agreement with experiments, and helped to improve the performance of the wind tunnel

Meteor studies in the framework of the JEM-EUSO program

Abstract We summarize the state of the art of a program of {UV} observations from space of meteor phenomena, a secondary objective of the JEM-EUSO international collaboration. Our preliminary analysis indicates that JEM-EUSO, taking advantage of its large {FOV} and good sensitivity, should be able to detect meteors down to absolute magnitude close to 7. This means that JEM-EUSO should be able to record a statistically significant flux of meteors, including both sporadic ones, and events produced by different meteor streams. Being unaffected by adverse weather conditions, JEM-EUSO can also be a very important facility for the detection of bright meteors and fireballs, as these events can be detected even in conditions of very high sky background. In the case of bright events, moreover, exhibiting some persistence of the meteor train, preliminary simulations show that it should be possible to exploit the motion of the {ISS} itself and derive at least a rough 3D reconstruction of the meteor trajectory. Moreover, the observing strategy developed to detect meteors may also be applied to the detection of nuclearites, exotic particles whose existence has been suggested by some theoretical investigations. Nuclearites are expected to move at higher velocities than meteoroids, and to exhibit a wider range of possible trajectories, including particles moving upward after crossing the Earth. Some pilot studies, including the approved Mini-EUSO mission, a precursor of JEM-EUSO, are currently operational or in preparation. We are doing simulations to assess the performance of Mini-EUSO for meteor studies, while a few meteor events have been already detected using the ground-based facility EUSO-TA