Mathematics for environmental problems: from modelling to applications

[EN]In this paper we summarize some aspects of the simplified physical wild fire spread model developed by the authors and of the Geographical Information System tool specially developed to provide a real usable wild fire spread tool based on this model.Conserjería de Educación de la Junta de Castilla y León; FEDER; Fundación General de la Universidad de Salamanc

Space-Time adaptive algorithm for the mixed parabolic problem

Se presenta una estimación a posteriori del error para el problema parabólico lineal, y se diseña el correspondiente algoritmo de adaptación de malla y paso de tiempo. Para la discretización espacial se utiliza el elemento de Raviart-Thomas de menor orden y para la integración temporal la aproximación de Galerkin discontinua con paso variable. Se aplican los métodos numéricos desarrollados a varios problemas significativos que muestran la eficiencia del algoritmo desarrollado.In this paper we present an a-posteriori error estimator for the mixed formulation of a linear parabolic problem, used for designing an efficient adaptive algorithm. Our space-time discretization consists of lowest order Raviart-Thomas finite element over graded meshes and discontinuous Galerkin method with variable time step. Finally, several examples show that the proposed method is efficient and reliable

Space-Time adaptive algorithmfor the mixed parabolic problem

Se presenta una estimación a posteriori del error para el problema parabólico lineal, y se diseña el correspondiente algoritmo de adaptación de malla y paso de tiempo. Para la discretización espacial se utiliza el elemento de Raviart-Thomas de menor orden y para la integración temporal la aproximación de Galerkin discontinua con paso variable. Se aplican los métodos numéricos desarrollados a variosproblemas significativos que muestran la eficiencia del algoritmodesarrollado.In this paper we present an a-posteriori error estimator for the mixed formulation of a linear parabolic problem, used for designing an efficient adaptive algorithm. Our space-time discretization consists of lowest order Raviart-Thomas finite element over graded meshes and discontinuous Galerkin method with variable time step. Finally, several examples show that the proposed method is efficient and reliable

Mobile Architecture for Forest Fire Simulation Using PhyFire-HDWind Model

[EN]This article presents the design and implementation of a new visualization system for mobile platforms for the PhyFire-HDWind fire simulation model, called AppPhyFire. It proposes a mobile computing infrastructure, based on ArcGIS Server and REST architecture, which improves the user experience in actions associated with the fire simulation process. The PhyFire-HDWind model, of which the system presented here forms part, is a forest fire propagation simulation tool developed by the SINUMCC research group of the University of Salamanca, based on two own simplified physical models, the PhyFire physical fire propagation model, and the HDWind high definition wind field model, resolved using efficient numerical and computational tools and parallel computing, allowing simulation times shorter than the real time fire propagation, integrated into a Geographical Information System, and accessible through a server by the AppPhyFire. The system presented in this article allows a quick visualization of simulations results in mobile devices. This work presents the detailed operation of the system and its phases of operation

Global sensitivity analysis of fuel-type-dependent input variables of a simplified physical fire spread model

[EN]A new global sensitivity analysis has been conducted of fuel-type-dependent input variables of the simplified physical fire spread model (PhyFire) to understand how the use of spatial averages, that is, fuel models, influences the results of PhyFire with a view to enhancing its understanding and improving its design. The model’s simplicity, the numerical techniques used, and a recent code optimisation, allow undertaking the analysis with very competitive computational times. The fuel data used correspond to grasslands, shrublands and forest in the Spanish region of Galicia. The analysis results validate the flame length sub-model proposed in the paper, which significantly improves the model’s efficiency

A downscale wind forecasting method based on WRF-HDMW coupling

[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.Junta de Castilla y león; Fondos FEDE

Validating the effect of fuel moisture content by a multivalued operator in a simplified physical fire spread model

[EN]Fuel moisture content (FMC) plays a significant role in wildfire behavior and rate of spread (ROS). In addition, FMC is a highly dynamic factor and very vulnerable to climate variations. Understanding the effect of FMC on the behavior of fire spread models is crucial, and detailed analysis of specific aspects of complex models is a very effective way to improve them. The simplified physical fire spread model PhyFire considers the effect of FMC in a novel way, involving a multivalued maximal monotone operator. Several numerical experiments have been carried out to confirm that the behavior of the ROS simulated with PhyFire involving FMC is as expected in the reviewed literature: an exponential decrease in fire ROS compared to FMC, for different scenarios, considering different fuel types, terrain slopes and wind speeds. PhyFire performs very accurately, proving that the multivalued operator used is suitable and consistent

A GIS-based fire spread simulator integrating a simplified physical wildland fire model and a wind field model

[EN]This article discusses the integration of two models, namely, the Physical Forest Fire Spread (PhFFS) and the High Definition Wind Model (HDWM), into a Geographical Information System-based interface. The resulting tool automates data acquisition, preprocesses spatial data, launches the aforementioned models and displays the corresponding results in a unique environment. Our implementation uses the Python language and Esri’s ArcPy library to extend the functionality of ArcMap 10.4. The PhFFS is a simplified 2D physical wildland fire spread model based on conservation equations, with convection and radiation as heat transfer mechanisms. It also includes some 3D effects. The HDWM arises from an asymptotic approximation of the Navier–Stokes equations, and provides a 3D wind velocity field in an air layer above the terrain surface. Both models can be run in standalone or coupled mode. Finally, the simulation of a real fire in Galicia (Spain) confirms that the tool developed is efficient and fully operational.Junta de Castilla y León; Fundación General de la Universidad de Salamanc

Neptuno ++: An Adaptive Finite Element Toolbox for Numerical Simulation of Environmental Problems

[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++.Junta de Castilla y León; Fondos FEDE

GIS-integrated environmental models

[EN]In this paper, we present the integration of the mathematical models Physical Forest Fire Spread (PhFFS) and High Definition Wind Model (HDWF), developed by the authors, into a GIS-based interface in order to supply to the end-user a func- tional and efficient tool. The resulting tool automates data acquisition, pre-processes spatial data, launches the aforementioned models, and displays the corresponding results in a unique environment. Our implementation uses the Python language and Esri’s ArcPy library to extend the functionality of ArcMap 10.4. The PhFFS is a simplified 2D physical wildland fire spread model based on conservation equations, with convection and radiation as heat transfer mechanisms. It also includes some 3D effects. The HDWF arises from an asymptotic approximation of the Navier-Stokes equations, and provides a 3D wind velocity field in an air layer above the terrain surface. Both models can be run in standalone or coupled mode. Finally, we confirm that the developed tool is efficient and fully operational presenting some examples of its successful application.Departamento de Educación de la Junta de Castilla y León; Fondos FEDER; Fundación General de la Universidad de Salamanc