Abstract
Flow simulationsin rivers are typically carried out using spatially-averaged quantities, which are affected by choice of grid structure. To isolate these effects, we set-up schematised river meanders with a flat bed in the transverse flow
direction. We considered curvilinear and triangular grids with a high, medium and low resolution for cases where floodplains are excluded. Next, curvilinear,triangular and hybrid (combination of curvilinear and triangular cells) grids with a high and medium resolution are applied in schematised rivers where floodplains are present. The analysis showed that lower depth-averaged flow velocities and higher water depths are simulated with coarser grids. The
numerical effects by the coarser grids are substantially larger in cases with distinct flow changes, such as in sharper river bends, and areas with high discharges per unit width. With the presence of floodplains, the latter decreases,
leading to a damping of the numerical effects created by the grid.
direction. We considered curvilinear and triangular grids with a high, medium and low resolution for cases where floodplains are excluded. Next, curvilinear,triangular and hybrid (combination of curvilinear and triangular cells) grids with a high and medium resolution are applied in schematised rivers where floodplains are present. The analysis showed that lower depth-averaged flow velocities and higher water depths are simulated with coarser grids. The
numerical effects by the coarser grids are substantially larger in cases with distinct flow changes, such as in sharper river bends, and areas with high discharges per unit width. With the presence of floodplains, the latter decreases,
leading to a damping of the numerical effects created by the grid.
| Original language | English |
|---|---|
| Title of host publication | Proceedings of the 1st IAHR Young Professionals Congress, 17-18 November 2020 |
| Editors | José María Carrillo, Eva Fenrich, David Ferràs, Silke Wieprecht |
| Publisher | IAHR |
| Pages | 226-227 |
| Number of pages | 2 |
| ISBN (Print) | 978-90-82484-6-63 |
| Publication status | Published - Nov 2020 |