INVESTIGADORES
ORFEO Oscar
congresos y reuniones científicas
Título:
Flow structures and processes in the Rio Paraná, Argentina
Autor/es:
SANDBACH, S.; ASHWORTH, P.; AMSLER, M.; BEST, J.; HARDY, R,; LANE, S.; NICHOLAS, A.; ORFEO, O.; PARSONS, D.; REESINK, A.; SMITH G, SAMBROOK; SZUPIANY, R,
Lugar:
Durham University, UK
Reunión:
Congreso; British Society for Geomorphology (BSG) Annual Conference; 2009
Institución organizadora:
Durham University
Resumen:
Our understanding of large rivers is limited due to the difficulties in obtaining field data at these large scales. Data rich results maybe obtained using computational fluid dynamic (CFD) models permitting the investigation of detailed flow patterns that would otherwise not be available. However, the application of these models to large rivers is not without its own complications and has yet to be fully developed. This is the result of two limiting factors, our inability; i) to design numerically stable meshes for complex topographies at these spatial resolutions; and; ii) to collect high resolution data appropriate for the boundary conditions of the numerical scheme. In this paper, a CFD model is used to investigate flow structures in the Rio Paran¨¢ (South America), the 6th largest river in the world. We have recently obtained bed topography using a single beam echo sounder and flow data using a Doppler current profiler. The data was collected for a 38 km reach in the middle part of the Paran¨¢ upstream of the Paraguay¨CParan¨¢ confluence. This data was used to provide both boundary conditions and validation for our model. The entire reach was modelled using a Reynolds-averaged Navier stokes (RANS) code modelling turbulence with a ¦Ê¨C¦Å RNG turbulence model within a Cartesian mesh. To include bed topography, a new five term mass flux scaling algorithm that modifies the mass conservation equation through a numerical porosity approach was applied. The advantage of this approach is that complex topography can be incorporated into the model maintaining a regular Cartesian discritization. The results demonstrate the importance of topographic forcing on determining flow structures in large rivers. Continuing research uses this processes information to inform parameterization of a reduced complexity model of the same reach. i) to design numerically stable meshes for complex topographies at these spatial resolutions; and; ii) to collect high resolution data appropriate for the boundary conditions of the numerical scheme. In this paper, a CFD model is used to investigate flow structures in the Rio Paran¨¢ (South America), the 6th largest river in the world. We have recently obtained bed topography using a single beam echo sounder and flow data using a Doppler current profiler. The data was collected for a 38 km reach in the middle part of the Paran¨¢ upstream of the Paraguay¨CParan¨¢ confluence. This data was used to provide both boundary conditions and validation for our model. The entire reach was modelled using a Reynolds-averaged Navier stokes (RANS) code modelling turbulence with a ¦Ê¨C¦Å RNG turbulence model within a Cartesian mesh. To include bed topography, a new five term mass flux scaling algorithm that modifies the mass conservation equation through a numerical porosity approach was applied. The advantage of this approach is that complex topography can be incorporated into the model maintaining a regular Cartesian discritization. The results demonstrate the importance of topographic forcing on determining flow structures in large rivers. Continuing research uses this processes information to inform parameterization of a reduced complexity model of the same reach.