INVESTIGADORES
ORFEO Oscar
congresos y reuniones científicas
Título:
Three-dimensional modelling of a very large river; the Rio Paran¨¢, 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:
Braunschweig, Germany
Reunión:
Congreso; IAHR River Flow 2010 Conference; 2010
Institución organizadora:
The International Association of Hydro-Environment Engineering and Research
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. Here, we test a new five-term mass-flux scaling algorithm for including bed topography in a very large river, where the discretised form of the mass and momentum equations are modified using a numerical porosity approach applied within a Cartesian framework. Converged solutions were obtained using a Reynolds-averaged Navier stokes (RANS) code modelling turbulence with a ¦Ê¨C¦Å RNG turbulence model. The input boundary conditions were supplied from a recent field investigation in the middle part of the Rio Paran¨¢ (South America) upstream of the Paraguay¨CParan¨¢ confluence. A 38 km long reach was investigated where topographic and velocity data was collected using an acoustic Doppler current profiler (aDcp) and a single beam echo sounder. In general there is good agreement between the modelled and field data. The results demonstrate the importance of topographic forcing on determining flow structures in large rivers and the difficulties of objective identification of secondary flows 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. Here, we test a new five-term mass-flux scaling algorithm for including bed topography in a very large river, where the discretised form of the mass and momentum equations are modified using a numerical porosity approach applied within a Cartesian framework. Converged solutions were obtained using a Reynolds-averaged Navier stokes (RANS) code modelling turbulence with a ¦Ê¨C¦Å RNG turbulence model. The input boundary conditions were supplied from a recent field investigation in the middle part of the Rio Paran¨¢ (South America) upstream of the Paraguay¨CParan¨¢ confluence. A 38 km long reach was investigated where topographic and velocity data was collected using an acoustic Doppler current profiler (aDcp) and a single beam echo sounder. In general there is good agreement between the modelled and field data. The results demonstrate the importance of topographic forcing on determining flow structures in large rivers and the difficulties of objective identification of secondary flows