 |
| Titel |
Large Eddy Simulation of the flow in 90\r{ } angled open-channel confluences
with discordant beds |
| VerfasserIn |
Pedro Ramos, Laurent Schindfessel, Tom De Mulder |
| Konferenz |
EGU General Assembly 2017
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250151354
|
| Publikation (Nr.) |
 EGU/EGU2017-15923.pdf |
|
|
|
|
|
| Zusammenfassung |
| The aim of the present contribution is to investigate the effect of difference in bed elevations
of the tributary and main channel in a 90˚ angled open-channel confluence onto the
hydrodynamics.
Large Eddy Simulations (LES) are used to investigate the three-dimensional complex
flow patterns for four different discordance ratios (ΔzT/hd = 0, 0.1, 0.25 and 0.4), with
geometries previously studied by other authors, whose data will be used for comparison
purposes. The values of the ratio between the upstream main channel discharge and the total
combined discharge varies between 0.083 and 0.917. With LES, it is possible to
resolve a portion of the turbulent motions, which is beneficial to the accuracy of the
simulations.
This contribution develops further analysis on some findings of the aforementioned
studies, mostly regarding the role of the bed discordance on the recirculation zone dimensions
and on the influence of the tributary flow on the main stream. Points of interest are the
orientation of the tributary’s inflow angle and the dimensions of the separation zone. These
parameters are important for the longitudinal momentum balance, which determines the head
losses occurring at the confluence. Additionally, the distribution of Turbulent Kinetic
Energy (TKE) and bed shear stresses are studied. Previous studied indicated that the
presence of a bed discordance has a pronounced effect on these points of interest. The
present contribution elaborates these findings and adds knowledge from time-resolved
simulations.
Since in a LES the flow and turbulence are for the most part resolved, it enables a
thorough study of the hydrodynamics in an open-channel confluence, of which the
understanding of the physical phenomena occurring in natural confluences will benefit. |
|
|
|
|
|
|