TY - GEN
T1 - Unsteady laminar flow with convective heat transfer through a rotating curved square duct with small curvature
AU - Mondal, Rabindra Nath
AU - Roy, Titob
AU - Shaha, Poly Rani
AU - Yanase, Shinichiro
N1 - Funding Information:
Rabindra Nath Mondal would gratefully acknowledge the financial support from the Japan Society for the Promotion of Science (JSPS), No. L15534, while Shinichiro Yanase expresses his cordial thanks to the Japan Ministry of Education, Culture, Sports, Science and Technology for the financial support through the Grant-in-Aid for Scientific Research, No. 24560196.
Publisher Copyright:
© 2016 Author(s).
PY - 2016/7/12
Y1 - 2016/7/12
N2 - Unsteady laminar flow with convective heat transfer through a curved square duct rotating at a constant angular velocity about the center of curvature is investigated numerically by using a spectral method, and covering a wide range of the Taylor number-300≤Tr≤1000 for the Dean number Dn = 1000. A temperature difference is applied across the vertical sidewalls for the Grashof number Gr = 100, where the outer wall is heated and the inner wall cooled, the top and bottom walls being adiabatic. Flow characteristics are investigated with the effects of rotational parameter, Tr, and the pressure-driven parameter, Dn, for the constant curvature 0.001. Time evolution calculations as well as their phase spaces show that the unsteady flow undergoes through various flow instabilities in the scenario 'multi-periodic → chaotic → steady-state → periodic → multi-periodic → chaotic', if Tr is increased in the positive direction. For negative rotation, however, time evolution calculations show that the flow undergoes in the scenario 'multi-periodic → periodic → steady-state', if Tr is increased in the negative direction. Typical contours of secondary flow patterns and temperature profiles are obtained at several values of Tr, and it is found that the unsteady flow consists of two-to six-vortex solutions if the duct rotation is involved. External heating is shown to generate a significant temperature gradient at the outer wall of the duct. This study also shows that there is a strong interaction between the heating-induced buoyancy force and the centrifugal-Coriolis instability in the curved channel that stimulates fluid mixing and consequently enhances heat transfer in the fluid.
AB - Unsteady laminar flow with convective heat transfer through a curved square duct rotating at a constant angular velocity about the center of curvature is investigated numerically by using a spectral method, and covering a wide range of the Taylor number-300≤Tr≤1000 for the Dean number Dn = 1000. A temperature difference is applied across the vertical sidewalls for the Grashof number Gr = 100, where the outer wall is heated and the inner wall cooled, the top and bottom walls being adiabatic. Flow characteristics are investigated with the effects of rotational parameter, Tr, and the pressure-driven parameter, Dn, for the constant curvature 0.001. Time evolution calculations as well as their phase spaces show that the unsteady flow undergoes through various flow instabilities in the scenario 'multi-periodic → chaotic → steady-state → periodic → multi-periodic → chaotic', if Tr is increased in the positive direction. For negative rotation, however, time evolution calculations show that the flow undergoes in the scenario 'multi-periodic → periodic → steady-state', if Tr is increased in the negative direction. Typical contours of secondary flow patterns and temperature profiles are obtained at several values of Tr, and it is found that the unsteady flow consists of two-to six-vortex solutions if the duct rotation is involved. External heating is shown to generate a significant temperature gradient at the outer wall of the duct. This study also shows that there is a strong interaction between the heating-induced buoyancy force and the centrifugal-Coriolis instability in the curved channel that stimulates fluid mixing and consequently enhances heat transfer in the fluid.
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U2 - 10.1063/1.4958362
DO - 10.1063/1.4958362
M3 - Conference contribution
AN - SCOPUS:84984568810
T3 - AIP Conference Proceedings
BT - International Conference on Mechanical Engineering
A2 - Morshed, A. K. M. Monjur
A2 - Ali, Mohammad
A2 - Akanda, Md. Abdus Salam
PB - American Institute of Physics Inc.
T2 - 11th International Conference on Mechanical Engineering, ICME 2015
Y2 - 18 December 2015 through 20 December 2015
ER -