Premium
Numerical exploration of flow topology and vortex stability in a curved duct
Author(s) -
Tsai S. F.,
Sheu Tony W. H.
Publication year - 2006
Publication title -
international journal for numerical methods in engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.421
H-Index - 168
eISSN - 1097-0207
pISSN - 0029-5981
DOI - 10.1002/nme.1959
Subject(s) - streamlines, streaklines, and pathlines , reynolds number , mechanics , vortex , flow (mathematics) , physics , secondary flow , instability , mathematics , curvature , geometry , classical mechanics , turbulence
We performed incompressible flow simulation in a square duct with 90° bend and a curvature radius of 2.3 to extend our understanding of the vortical flow development in the bend. The solutions for the flow investigated at the Reynolds number of Re =790 are obtained in a tri‐quadratic element system, where velocities stagger the pressure working variable, using the streamline‐upwind finite element model and the BiCGSTAB iterative solver. The simulated results reveal that centrifugal force convects the quickly moving fluid particles towards the outer wall. The axial velocity, as a result, shows twin peaks in the curved channel. At about θ=66°, the secondary flow shows three complex pairs of vortices. Also noteworthy is the formation of a downstream spiralling flow motion. To better elucidate the dominating three‐dimensional flow nature, the topological study of limiting streamlines was undertaken. Insight into the longitudinal flow instability is gained by tracking the formation and diminishing of limiting cycles. Copyright © 2006 John Wiley & Sons, Ltd.