Numerical modelling of separated flow in river bends: model testing and experimental investigation of geometric controls on the extent of flow separation at the concave bank
✍ Scribed by A. Hodskinson; R. I. Ferguson
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 353 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0885-6087
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✦ Synopsis
The occurrence of separated ¯ow in sharply curving river bends, and the associated deposition of ®ne-grained sediment, is widely recognized, but the factors controlling the existence and extent of separated ¯ow have not been clearly identi®ed. A three-dimensional, ®xed lid computational ¯uid dynamics program was used to simulate time-averaged ¯ow in idealized channel bends in order to investigate geometric controls on ¯ow separation. The code was applied ®rst to a ®eld site; it successfully modelled the qualitative features of the ¯ow, including a separation zone, and was insensitive to choice of turbulence closure or exclusion of lateral variation in water surface topography. The simulations of idealized bends demonstrate that the existence and extent of concave bank ¯ow separation can be signi®cantly in¯uenced by changes in bend planform, point bar topography and upstream planform.