Numerical stability problems in hydrodynamic modelling of confluences with small junction angles
Само за регистроване кориснике
2009
Конференцијски прилог (Објављена верзија)
,
Universidad de Concepción
Метаподаци
Приказ свих података о документуАпстракт
The paper addresses problems which arise from the use of 3D grids with quadrilateral faces on
the horizontal planes in hydrodynamic modelling of discordant beds asymmetrical confluences
with small junction angles. There are two sources of instabilities: a) steep gradients that develop
near the backward facing step at the tributary entrance to the confluence and b) skewness of the
cell faces on the horizontal planes. In previous studies of the concordant beds confluences the
junction-angle of 45 was reported as the angle which still provides stable solution. In this paper,
the limit value is redefined, and the minimal percentages of the post-confluence channel widening, necessary for obtaining stable solution, are defined for the set of small junction angles.
Additionally, the practical consequences of artificial channel widening are discussed in detail.
An attempt is made to reconstruct the profiles of the: a) minimal and maximal u-, v- and w-
velocity values and b) non-d...imensional bed shear stress for the case with no post-confluence
channel widening.
Кључне речи:
3D grids with quadrilateral faces / numerical instability / backward facing step / skewness of the cell faces / small junction angle / artificial post-confluence channel wideningИзвор:
Proceedings of the 8th International Conference on Hydroinformatics – HIC 2009, 2009, 1/40-10Издавач:
- Universidad de Concepción
Финансирање / пројекти:
- Управљање водним акумукацијама и њихова заштита (RS-22011)
- Ризици у примени Оквирних директива Европске уније у Републици Србији (RS-22017)