http://hdl.handle.net/10366/138161 2026-04-21T06:07:44Z http://hdl.handle.net/10366/138213 [EN]In this paper, an adaptive solar radiation numerical model for complex terrains is described. 2018-06-01T00:00:00Z http://hdl.handle.net/10366/138212 [EN]A mass consistent wind model is improved by introducing three items: the new 3-D mesh generator MECCANO applied to complex terrains, the current atmospheric stability definition by Zilitinkevich including new wind profiles, and a specific preconditioner for the linear systems arising in a wind model. 2018-06-01T00:00:00Z http://hdl.handle.net/10366/138207 2016-06-01T00:00:00Z http://hdl.handle.net/10366/138206 [en]In this work we propose to apply ensemble methods to a local scale adaptive wind forecasting model. 2016-06-01T00:00:00Z http://hdl.handle.net/10366/138205 2016-06-01T00:00:00Z http://hdl.handle.net/10366/138204 [ES]En esta conferencia se introducen ideas básicas sobre la simulación numérica, mediante el método de los elementos finitos (MEF), de problemas medioambientales que han sido abordados por nuestro grupo en diversos proyectos de investigación sobre simulación de campos de viento, radiación solar, contaminación atmosférica y la modelización de yacimientos de petróleo. 2017-02-01T00:00:00Z http://hdl.handle.net/10366/138203 [EN]We present a new strategy for construction spline spaces over hierarchical T-meshes with quad- and octree subdivision scheme. 2017-04-01T00:00:00Z http://hdl.handle.net/10366/138182 [EN]In this conference, we present the main advances in the meccano method, which was introduced by the authors in 2006 for tetrahedral mesh generation. 2018-06-01T00:00:00Z http://hdl.handle.net/10366/138181 [EN]This lecture is a survey concerning different numerical methods to solve free boundary problems, mainly focussing in: Solving variational inequalities Adaptive Finite Element methods Level set methods 2018-06-01T00:00:00Z http://hdl.handle.net/10366/138180 [EN]In this talk, we show some of the main features of Neptuno++, through several examples. Neptuno++ is a finite element toolbox mainly developed by L. Ferragut at SINUMCC (Group of Numerical Simulation and Scientific Computation) and implemented in C++. 2018-06-01T00:00:00Z http://hdl.handle.net/10366/138179 [EN]We present a historical review of PhyFire and HDWind, both models developed by the research group on Numerical Simula- tion and Scientific Computation founded by L. Ferragut at the University of Salamanca. 2018-06-01T00:00:00Z http://hdl.handle.net/10366/138176 [EN]Urban air quality simulation requires models with di erent characteristics to those used in mesoscale or microscale. The spatial discretisation resolution is one of them. Urban geometries require smaller elements than those in other scales. Mesh for this kind of geometries are generated using the Meccano method; a mesh generator that has generated high-quality meshes of complex geometries [1]. In this work, we have added capabilities to insert buildings into the mesh maintaining the element quality. Wind eld should also be suitable for urban scale. To this end, we will use a mass-consistent model [2]. Thisapproximation has performed e ciently in microscale problems, coupling with mesoscale numerical weather prediction models. Finally, an adaptive nite element method is used to simulate the convection-di usion-reaction equation [3, 4]. The problem can be convectiondominant, so it is stabilised using a Least-Squares nite element method. The resulting matrix is symmetric and is solved using the Conjugate Gradient method preconditioned with an incomplete Cholesky factorisation. The model is applied to the city of Las Palmas de Gran Canaria. 2018-06-01T00:00:00Z http://hdl.handle.net/10366/138175 [EN]We propose a new algorithm on distributed-memory parallel computers for our simultaneous untangling and smoothing of tetrahedral meshes [9, 10]. A previous parallel implementation on shared-memory computers is analyzed in [1]. The new parallel procedure takes ideas from Freitag et al. strategy [11]. The method is based on: partitioning a mesh, optimizing interior vertices, optimizing boundary vertices of interior partitions, and communicating updated coordinates of boundary vertices. This paper presents performance evaluation results of our parallel algorithm. We apply the procedure in the mesh generation of several 3-D objects by using the Meccano method [4]. High levels of speed-up are obtained in the mesh optimization step of this method. How ever, several bottlenecks may limit the parallelism. We provide some hypotheses about the factors that cause more parallel overhead. The relative number of elements, that are located at the interfaces of the sub-domains of the object, is one of the more important aspects for the e ciency of the parallel mesh optimization. 2018-06-01T00:00:00Z http://hdl.handle.net/10366/138174 [EN]In this paper, we propose a wind prediction strategy based on a mesoscale-microscale coupling technique. We will use the Weather Research and Forecast (WRF) [3] prediction as input data for the High Wind Defintion Model (HWDM) [2] to yield the forecast on a wind farm. 2017-07-01T00:00:00Z http://hdl.handle.net/10366/138173 [EN]In this paper, we present a new method to insert open surfaces into an existing tetrahedral mesh generated by the meccano method. The surfaces must be totally immersed in the mesh and must not intersect between them. The strategy includes a mesh refinement to obtain an initial approximation of each surface capturing its geometric features, the projection of the nodes from the approximation onto the actual surface, and the mesh optimization. The proposed method provides a high-quality conformal mesh with interpolations of the inserted surfaces. These approximations are suitable for operations where roughness is a major problem and a smoother solution is required, such as the estimation of normal vectors or the imposition of Neumann conditions. 2017-06-01T00:00:00Z http://hdl.handle.net/10366/138172 [EN]For wind field simulation with isogeometric analysis, firstly it is necessary to generate a spline parameterization of the computational domain, which is an air layer above the terrain surface. This parameterization is created with the meccano method from a digital terrain model. The main steps of the meccano method for tetrahedral mesh generation were introduced in [1, 2]. Based on the volume parameterization obtained by the method, we can generate a mapping from the parametric T-mesh to the physical space [3, 4]. Then, this volumetric parameterization is used to generate a cubic spline representation of the physical domain for the application of isogeometric analysis. We consider a mass-consistent model [5] to compute the wind field simulation in the three-dimensional domain from wind measurements or a wind forecasted by a meteorological model (for example, WRF or HARMONIE). From these data, an interpolated wind field is constructed. The mass-consistent model obtains a new wind field approaching the interpolated one, but verifying the continuity equation (mass conservation) for constant density and the impermeabilitycondition on the terrain. This adjusting problem is solved by introducing a Lagrange multiplier, that is the solution of a Poisson problem. The resulting field is obtained from the interpolated one and the gradient of the Lagrange multiplier. It is well known that if we use classical Lagrange finite elements, the gradient of the numerical solution is discontinuous over the element boundary. The advantage of using isogeometric analysis with cubic polynomial basis functions [6, 7] is that we obtain a C2 continuity for the Lagrange multiplier in the whole domain. In consequence, the resulting wind field is better approximated. Applications of the proposed technique are presented. 2017-06-01T00:00:00Z