Three-dimensional flow structure at fixed 70° open-channel confluence with bed discordance
This experimental study provides a characterization of the flow field created by bed discordance at a fixed 70∘ open-channel confluence on the basis of detailed free surface topography and three-component acoustic Doppler velocimetry measurements, which are contrasted with the results for a concorda...
| Autores: | , , , , |
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| Tipo de documento: | artigo |
| Estado: | Versión aceptada para publicación |
| Data de publicação: | 2020 |
| País: | España |
| Recursos: | Universidad Politécnica de Cartagena(UPCT) |
| Repositório: | Repositorio Digital UPCT |
| OAI Identifier: | oai:repositorio.upct.es:10317/13338 |
| Acesso em linha: | http://hdl.handle.net/10317/13338 https://www.tandfonline.com/doi/full/10.1080/00221686.2019.1596988 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Acoustic Doppler velocimetry Bed discondance Hydrodynamics Open channel confluences Secondary motion Helical cell Ingeniería Hidráulica 2506.07 Geomorfología 3301.12 Hidrodinámica |
| Resumo: | This experimental study provides a characterization of the flow field created by bed discordance at a fixed 70∘ open-channel confluence on the basis of detailed free surface topography and three-component acoustic Doppler velocimetry measurements, which are contrasted with the results for a concordant bed junction. Due to bed discordance, the jet-like flow from the tributary is bent downstream to be aligned with the main channel axis. Underneath the tributary backward-facing step, separation occurs, producing negative vorticity along the main channel axis. A strong secondary motion downstream of the tributary junction is related to flow separation at the step and to flow release from the jet-like flow induced by a difference in the curvature of jet-like motion. A quantification of the terms in the equation of conservation of the longitudinal vorticity shows that the vortex stretching terms are sufficient to explain the development of the helical motion, which is thus classified as a secondary motion of Prandtl's first kind. |
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