Proceedings of the
International Conference on Mechanical Engineering 2009
(ICME2009) 26- 28 December 2009, Dhaka, Bangladesh
 

ICME09-FM-15

FLOW THROUGH A CURVED RECTANGULAR DUCT
 

R. Nath Mondal, B. Roy and A. Kumar Datta
Mathematics Discipline; Science, Engineering and Technology School,
Khulna University, Khulna, Bangladesh

ABSTRACT

Flow through a curved rectangular duct of aspect ratios 0.5 ≤ l ≤ 1.5 is investigated numerically by using a spectral and covering a wide range of the Dean number. First, bifurcation structure of the steady solutions is investigated. As a result, a number of steady solution branches with asymmetric two-vortex and symmetric two- and multi-vortex solutions are obtained. The main concern of the present study is to investigate the transitional behavior of the unsteady solutions such as periodic, multi-periodic and chaotic solutions, as the aspect ratio changes. Time evolution calculations as well as their phase spaces show that the steady flow turns into chaotic flow through periodic and multi-periodic flows, if the Dean number is increased no matter what the aspect ratio is. It is found that the flow oscillates periodically or aperiodically between two-, four-, six-, eight- and ten-vortex solutions, as the aspect ratio is increased. It is also found that the axial flow shifted at the outer wall of the duct as the Dean number is increased.
 

Keywords: Curved Duct, Secondary Flow, Time Evolution, Periodic Solution, Chaos.

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