Documents published in Scipedia

• Integration of 1D and 2D finite volume schemes for computations of water flow in natural channels

  E. Bladé, M. Valentín, J. Dolz, J. Aragón-Hernández, G. Corestein, M. Juny

  Advances in Water Resources (2012). Vol. 42, pp. 17-29

  
  

  Abstract

  A wide variety of flood simulation models are available nowadays. Some of them use a 1D approach and others a 2D one, but there are also some which allow the performance of integrated 1D–2D simulations. These latter models, which have important advantages in optimizing computational costs, commonly use the 1D approach in river channels and the 2D one in floodplains. The coupling of 1D and 2D flows usually ensures mass conservation and makes use of simplified weir-type or friction slope equations, but neglects momentum transfer between the two domains. This paper presents a fully conservative method for the coupling of 1D and 2D domains to be used in numerical schemes based on finite volumes. The method, based on a discretization of the numerical fluxes which ensures the conservation of mass and momentum, is verified with simple test cases. The proposed scheme is compared with the standard method based on the source term of the equations and is applied to the hydrodynamic characterization of a river-reservoir system situated in the River Ebro in Spain.

  Abstract
  A wide variety of flood simulation models are available nowadays. Some of them use a 1D approach and others a 2D one, but there are also some which allow the performance of [...]

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• ASAR polarimetric, multi-incidence angle and multitemporal characterization of Doñana wetlands for flood extent monitoring

  B. Martí-Cardona, C. López-Martínez, J. Dolz, E. Bladé

  Remote Sensing of Environment (2010). Vol. 114 (11), pp. 2802-2815

  
  

  Abstract

  Doñana National Park wetlands, in South West Spain, undergo yearly cycles of inundation and drying out. During the hydrological year 2006–2007, 43 ASAR/Envisat images of Doñana, mostly in HH and VV polarizations, were acquired with the aim to monitor the flood extent evolution during an entire flooding cycle. The images were ordered in the seven ASAR incidence angles, also referred to as swaths, to achieve high observation frequency. In this study, backscattering temporal signatures of the main land cover types in Doñana were obtained for the different incidence angles and polarizations. Plots showing the σ0HH/σ0VV ratio behavior were also produced. The signatures were analyzed with the aid of miscellaneous site data in order to identify the effect of the flooding on the backscattering. Conclusions on the feasibility to discriminate emerged versus flooded land are derived for the different incidence angles, land cover types and phenological stages: intermediate incidence angles (ASAR IS3 and IS4) came up as the most appropriate single swaths to discriminate open water surface from smooth bare soil in the marshland deepest areas. Flood mapping in pasture lands, the most elevated regions, is feasible at steep to mid incidence angles (ASAR IS1 to IS4). In the medium elevation zones, colonized by large helophytes, shallow incidence angles (ASAR IS6 and IS7) enable more accurate flood delineation during the vegetation growing phase. Since Doñana land covers require different observation swaths for flood detection, the composition of different incidence angle images close in time provides the optimum flood mapping. Such composition is possible four times per ASAR 35-day orbit cycle, using pairs of 12-h apart IS1/IS6 and IS2/IS5 Doñana images.

  Abstract
  Doñana National Park wetlands, in South West Spain, undergo yearly cycles of inundation and drying out. During the hydrological year 2006–2007, 43 ASAR/Envisat [...]

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• Dam wall break simulation by means of a high resolution algorithm applied to the La Parota dam, Guerrero, Mexico

  M. Arganis, E. Bladé, J. Dolz, M. Juny, O. Fuentes, V. Franco, F. Luna-Cruz

  Ingeniería Hidráulica en México (2009). Vol. XXIV (3), pp. 101-106

  
  

  Abstract

  This document presents a dam wall break simulation of the La Parota hydropower project in Guerrero, Mexico, by means of the CARPA system, which is based in a 2D WAF-TVD (Weight Averaged Flux-Total Variation Diminishing) high resolution finite volume numerical scheme. With the results, it is possible to produce maps containing water depth, flow velocity, and affected zones, which are useful in the civil protection field.

  Abstract
  This document presents a dam wall break simulation of the La Parota hydropower project in Guerrero, Mexico, by means of the CARPA system, which is based in a 2D WAF-TVD (Weight [...]

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• Preserving steady-state in one-dimensional finite-volume computations of river flow

  E. Bladé, M. Gómez, M. Sánchez-Juny, J. Dolz

  Journal of Hydrology Engineering (2008). Vol. 134 (9), pp. 1343-1347

  
  

  Abstract

  When using finite-volume methods and the conservative form of the Saint Venant equations in one-dimensional flow computations, it is important to establish the correct balance between the discretized flux vector and the geometric source terms. Over the last few years various improvements to numerical schemes have been presented to achieve this correct balance, focusing on the capability to simulate water at rest on irregular geometries (C-property). In this paper it is shown that common schemes can lead to energy-violating solutions in the case of steady flow. We present developments based on the Roe TVD finite-volume scheme for one-dimensional Saint Venant equations, which results in a method that not only satisfies the C-property, but also preserves the correct steady flow when stationary boundary conditions are used. We also present a totally irregular channel test case for the verification of the method.

  Abstract
  When using finite-volume methods and the conservative form of the Saint Venant equations in one-dimensional flow computations, it is important to establish the correct balance [...]

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• Analysis of pressures on a stepped spillway

  M. Juny, E. Bladé, J. Dolz

  Journal of Hydrology (2008). Vol. 46 (3), pp. 410-414

  
  

  Abstract

  The pressure profiles on the horizontal and vertical step faces of a stepped spillway in the fully developed skimming flow region were measured. These observations allow to provide generalized equations that enable designers to analyze the amount and the location of negative pressures along the steps. The step locations subjected to negative pressure are also discussed including an analysis of the duration of the negative pressures. On the horizontal step faces, negative pressure were only observed on their upstream half for dimensionless discharges larger than dc/h = 1.3. On the vertical step faces, only the region close to the adjacent horizontal face was not subjected to negative pressure

  Abstract
  The pressure profiles on the horizontal and vertical step faces of a stepped spillway in the fully developed skimming flow region were measured. These observations allow to [...]

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• Pressures on a stepped spillway

  M. Juny, E. Bladé, J. Dolz

  Journal of Hydraulic Research (2007). Vol. 45 (4), pp. 505-511

  
  

  Abstract

  This paper presents an analysis of the pressure field on the steps of a stepped spillway on an RCC dam. The fundamental component of this study is a series of pressure measurements obtained in the fully-developed zone of skimming flow regime along a reduced-size stepped spillway model constructed at the Department of Hydraulic, Maritime and Environmental Engineering Laboratory of the Technical University of Catalonia (UPC). A mathematical model was fitted to the pressure profiles on the horizontal and vertical faces of the steps. This equation allows designers to estimate the possible negative values of pressure on the vertical and horizontal faces of the steps in the fully-developed zone of skimming flow regime.

  Abstract
  This paper presents an analysis of the pressure field on the steps of a stepped spillway on an RCC dam. The fundamental component of this study is a series of pressure measurements [...]

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• Modelación del flujo en lámina libre sobre cauces naturales. Análisis integrado en una y dos dimensiones

  E. Bladé, M. Valentín

  Monograph CIMNE (2006). M97

  
  

  Abstract

  En esta monografía se presenta un trabajo de desarrollo de herramientas de modelación numérica realizado dentro del grupo de investigación FLUMEN, en la E.T.S. de Ingenieros de Caminos, Canales y Puertos de Barcelona, destacando la integración de esquemas numéricos en una y dos dimensiones. El objetivo principal es la puesta a punto de una herramienta para la modelación matemática del flujo de agua en lámina libre, en régimen variable, con geometrías irregulares como son los cauces naturales (programa CARPA).

  Abstract
  En esta monografía se presenta un trabajo de desarrollo de herramientas de modelación numérica realizado dentro del grupo de investigación FLUMEN, [...]

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