Due to widespread applications of the bent ducts in engineering fields such as in chemical,mechanical,bio-mechanical and bio-medical engineering,scientists have paid considerable attention to invent new characteristic...Due to widespread applications of the bent ducts in engineering fields such as in chemical,mechanical,bio-mechanical and bio-medical engineering,scientists have paid considerable attention to invent new characteristics of fluid flow in a bent duct(BD).In the ongoing study,a spectral-based numerical technique is applied to explore flow characteristics and energy distribution through a loosely bent square duct(BSD)of small curvature.Flow is accelerated due to combined action of the non-dimensional parameters;the Grashof number Gr(=1000),the curvatureδ(=0.001),and the Prandtl number Pr(=7.0)over a wide domain of the Dean number 0<Dn≤5000.Fortran code is developed for the numerical computations and Tecplot software with Gost Script and Gost View is used for the post-processing purpose.The numerical study investigates steady solutions(SS)and as a result,a structure of six-branches of SSs composed of 2-to 6-vortex solutions is obtained.Then oscillating behavior with flow transition is discussed by obtaining timedependent solutions followed by power-spectrum analysis.Results showthat the trend of unsteady flow(UF)undergoes in the sequence‘steady-state→multi-periodic→steady-state→chaotic→multi-periodic→chaotic’,if Dn is increased.Asymmetric 2-to 4-vortex solutions are obtained for UF.Convective heat transfer(CHT)is then examined obtaining temperature gradients and energy contours,and it is found that CHT is significantly enhanced by the secondary flow(SF).The present study reveals that the role of secondary vortices over heat transfer(HT)is highly significant and HT occurs substantially for the chaotic solutions.Finally,for the interest of validation,the present numerical result is compared with the previously published experimental outcomes,and a good agreement is remarked.展开更多
文摘Due to widespread applications of the bent ducts in engineering fields such as in chemical,mechanical,bio-mechanical and bio-medical engineering,scientists have paid considerable attention to invent new characteristics of fluid flow in a bent duct(BD).In the ongoing study,a spectral-based numerical technique is applied to explore flow characteristics and energy distribution through a loosely bent square duct(BSD)of small curvature.Flow is accelerated due to combined action of the non-dimensional parameters;the Grashof number Gr(=1000),the curvatureδ(=0.001),and the Prandtl number Pr(=7.0)over a wide domain of the Dean number 0<Dn≤5000.Fortran code is developed for the numerical computations and Tecplot software with Gost Script and Gost View is used for the post-processing purpose.The numerical study investigates steady solutions(SS)and as a result,a structure of six-branches of SSs composed of 2-to 6-vortex solutions is obtained.Then oscillating behavior with flow transition is discussed by obtaining timedependent solutions followed by power-spectrum analysis.Results showthat the trend of unsteady flow(UF)undergoes in the sequence‘steady-state→multi-periodic→steady-state→chaotic→multi-periodic→chaotic’,if Dn is increased.Asymmetric 2-to 4-vortex solutions are obtained for UF.Convective heat transfer(CHT)is then examined obtaining temperature gradients and energy contours,and it is found that CHT is significantly enhanced by the secondary flow(SF).The present study reveals that the role of secondary vortices over heat transfer(HT)is highly significant and HT occurs substantially for the chaotic solutions.Finally,for the interest of validation,the present numerical result is compared with the previously published experimental outcomes,and a good agreement is remarked.
