Numerical stability problems in hydrodynamic modelling of confluences with small junction angles
Samo za registrovane korisnike
2009
Konferencijski prilog (Objavljena verzija)
,
Universidad de Concepción
Metapodaci
Prikaz svih podataka o dokumentuApstrakt
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.
Ključne reči:
3D grids with quadrilateral faces / numerical instability / backward facing step / skewness of the cell faces / small junction angle / artificial post-confluence channel wideningIzvor:
Proceedings of the 8th International Conference on Hydroinformatics – HIC 2009, 2009, 1/40-10Izdavač:
- Universidad de Concepción
Finansiranje / projekti:
- Upravljanje vodnim akumukacijama i njihova zaštita (RS-22011)
- Rizici u primeni Okvirnih direktiva Evropske unije u Republici Srbiji (RS-22017)