Numerical study of unsteady fluid flow through a tightly coiled rectangular duct of large aspect ratio
- 25 February 2021
- conference paper
- conference paper
- Published by AIP Publishing in AIP Conference Proceedings
- Vol. 2324 (1), 040006
- https://doi.org/10.1063/5.0037787
Abstract
In this paper, a viscous incompressible fluid flow through a tightly coiled rectangular duct of large aspect ratio has been studied numerically by using a spectral method and covering a wide range of the pressure gradient parameter, the Dean number, Dn (0 < Dn ≤ 1000) for both isothermal and non-isothermal flow. For non-isothermal flow, a temperature difference is applied across the vertical sidewalls for the Grashof number Gr =1000, where the outer wall is heated and the inner wall cooled. The main concern of this paper is to investigate effects of aspect ratio on time-dependent solutions such as steady-state, periodic, multi-periodic or chaotic. To investigate non-linear behavior of the unsteady solutions, time evolution calculations are performed and flow transition between two types of solutions is determined by drawing the phase space of the time-dependent solutions. The study shows that if Dn is small, the flow is steady-state whether the flow is isothermal or non-isothermal. However, as Dn increases, the flow undergoes in the scenario ‘steady-state ⃗ periodic ⃗chaotic’. Secondary flow patterns, axial flow distribution and temperature profiles on the unsteady flow characteristics are also obtained and it is found that the time-dependent flow consists of asymmetric two- to eight-vortex solutions. Distribution of the time dependent solutions is shown in the Dean number vs. vortex-structure plane for both isothermal and non-isothermal flows. Finally, our numerical results are validated with the experimental investigations obtained so far.Keywords
This publication has 13 references indexed in Scilit:
- Pressure-driven flow instability with convective heat transfer through a rotating curved rectangular duct with differentially heated top and bottom wallsPublished by AIP Publishing ,2019
- Flow development in curved rectangular ducts with continuously varying curvatureExperimental Thermal and Fluid Science, 2016
- ON THE ONSET OF DEAN VORTICES AND UNSTEADY SOLUTIONS THROUGH A CURVED RECTANGULAR DUCT OF LARGE ASPECT RATIOInternational Journal of Engineering and Applied Sciences, 2015
- Analysis of Secondary Flow Instability and Forced Convection in Fluid Flow Through Rectangular and Elliptical Curved DuctsHeat Transfer Engineering, 2013
- Numerical Prediction of Non-Isothermal Flow Through a Curved Square DuctInternational Journal of Fluid Mechanics Research, 2010
- Effects of Curvature and Convective Heat Transfer in Curved Square Duct FlowsJournal of Fluids Engineering, 2006
- On the Bifurcation of Laminar Flows through a Curved Rectangular TubeJournal of the Physics Society Japan, 1988
- Flow in curved pipes.JSME International Journal, 1987
- Flow in Curved PipesAnnual Review of Fluid Mechanics, 1983
- XVI.Note on the motion of fluid in a curved pipeThe London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 1927