Effects of aspect ratio on unsteady solutions through curved duct flow

Mondal, Rabindra Nath; Islam, Shams Ul; Uddin, K. M. Salah; Hossain, M. A.

doi:10.1007/s10483-013-1731-8

Cited by 30 publications

(19 citation statements)

References 22 publications

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“…In a convinced precise flow agreement and beyond, an extra couple of counter-rotating vortices develop at the exterior wall of the duct which is widely entitled as Dean Vortices [5]. Many theoretical and experimental studies have been conducted by considering this flow; for example, the articles by Berger et al [6], Mondal et al [7,8] and Chen et al [9] may be referenced.…”

Section: Introductionmentioning

confidence: 99%

“…Flow visualization in the range of Dean numbers from 50 to 500 was conducted in their experiment. Mondal et al [7] applied spectral method to study non-isothermal flow through a stationary curved rectangular duct of aspect ratios 1 to 3, and showed that the steady-state flow turns into chaotic flow through various flow instabilities if the aspect ratio is increased. Very recently, Islam et al [23] conducted spectral numerical study of Dean-Taylor flow through a rotating coiled rectangular duct, where they performed unsteady solutions of the flow for both rotating and co-rotating cases and discussed the role of secondary vortices on convective heat transfer.…”

Section: Introductionmentioning

confidence: 99%

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On the Onset of Hydrodynamic Instability with Convective Heat Transfer Through a Rotating Curved Rectangular Duct

Ray¹,

Hasan²,

Mondal³

2020

MMEP

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The present paper addresses numerical prediction of hydrodynamic instability with convective heat transfer through a rotating curved rectangular duct of curvature 0.1.The bottom wall of the duct is heated while cooling from the ceiling. Numerical calculations are carried out by using a spectral method and covering a wide range of the Taylor number 0 2000 Tr  for the constant pressure gradient force, the Dean number, 1000 Dn = .First, solution structure of the steady solutions is investigated. As a result, three branches of asymmetric steady solutions with two-to ten-vortex solutions are obtained by using Newton-Raphson iteration method. Then unsteady solutions are obtained by time evolution calculations and flow transitions are well justified by obtaining the phase space and power spectrum of the solutions. It is found that chaotic flow turns into steady-state flow through periodic oscillating flow, if Tr is increased. Streamlines and isotherms are also obtained at several values of Tr, and it is found that the unsteady flow consists of two-to ten-vortex solutions. The present study shows that combined action of the centrifugal-Coriolis-buoyancy forces contribute to generate the vorticity. The present study exposes the role of secondary vortices on convective heat transfer, which shows that convective heat transfer is significantly enhanced by the secondary flow; and the chaotic flow, which occurs at small Tr but at large Dn, enhances heat transfer more effectively than the steady-state or periodic solutions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the Onset of Hydrodynamic Instability with Convective Heat Transfer Through a Rotating Curved Rectangular Duct

Ray¹,

Hasan²,

Mondal³

2020

MMEP

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“…They showed that as the Dean number increases, finite random disturbances lead the flows from a stable steady state to another stable steady state, a periodic oscillation, an intermittent oscillation, another periodic oscillation and a chaotic oscillation. Mondal et al [23] applied spectral method to study non-isothermal flow through a curved rectangular duct of aspect ratios 1 to 3, and showed that the steady-state flow turns into chaotic flow through various flow instabilities if the aspect ratio is increased. Recently, a combined experimental and numerical study was conducted by Li et al [24] to better understand the 3-D flow development in 120° curved rectangular ducts with continuously varying curvature.…”

Section: Introductionmentioning

confidence: 99%

Numerical Prediction of Non-isothermal Flow with Convective Heat Transfer Through a Rotating Curved Square Channel with Bottom Wall Heating and Cooling from the Ceiling

Hasan¹,

Mondal²,

Lorenzini³

2019

IJHT

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The present paper investigates numerical simulation of fluid flow and heat transfer through a rotating curved square channel of curvature ratios ranging from 0.001 to 0.5. Crank-Nicolson and Adams-Bashforth methods together with the function expansion and the collocation methods are applied to obtain the numerical solution. The bottom wall of the channel is heated while cooling from the ceiling. The channel is rotated in the positive direction for the Taylor number 0 2000 Tr  and combined effects of the centrifugal, Coriolis and buoyancy forces are investigated. As a result, two branches of asymmetric steady solutions comprising with two-to multi-vortex solutions are obtained. Linear stability analysis shows that the flow is stable only for a small region 164.82 601.62 Tr  while unstable otherwise. In the unstable region, time-dependent solutions are obtained and flow transitions are well determined by obtaining power spectrum density of the solutions and it is found that the timedependent flow undergoes through various flow instabilities, if Tr is increased in the positive direction. The results clearly show the existence of multiple Dean vortices along the duct while axial velocity profile is related to the outer Dean vortices, the wall pressure is more influenced by the Dean vortices attached to the outer concave wall. The present study elucidates the role of secondary vortices on convective heat transfer which shows that convective heat transfer is significantly enhanced by the secondary flow; and the chaotic flow, which takes place at large Tr's, enhances heat transfer more efficiently than the steady-state or periodic solutions. This study also reveals that there is a sharp influence between the ardor-induced buoyancy force and centrifugal-Coriolis instability in the rotating curved channel that inspires fluids mixing and consequently enhances heat transfer in the fluid. Finally, our numerical results are compared with the experimental investigations, and it is found that there is a good agreement between the numerical and experimental data.

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“…Furthermore, the heat and mass transport phenomena have been inspected by diverse authors in recent time. For details one can refer the followings [18,19]. To the best of authors' idea, the investigation of comprehensive comparison of unsteady MHD radiative boundary layer Casson and Williamson fluid flow yields an inclined cylinder has kept unexplored.…”

Section: Introductionmentioning

confidence: 99%

MHD Radiative Flow of Casson and Williamson Nanofluids over an Inclined Cylindrical Surface with Chemical Reaction Effects

Sarkar¹,

Reza‐E‐Rabbi²,

Arifuzzaman³

et al. 2019

IJHT

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This study exhibited the investigation of magnetohydrodynamics (MHD) boundary layer phenomenon of Casson and Williamson nanofluids, which was flowing on an inclined cylindrical surface. The impact of linear order chemical reaction with thermal radiation had been considered in multiphase flows. By taking the assistance of compact visual FORTRAN 6.6a programming algorithm, the finite scheme was imposed explicitly for attaining the dimensionless form of the fundamental equations. The convergence criterion had also been established for the exactness of the pertinent parameters. It was observed that the ongoing work converged for Lewis number 0.036 Le ≥ and Prandtl number Pr 0.52 ≥ . A tabular comparison had been presented to validate the numerical modelling, and a favourable result was attained. The obtained outcomes were analysed for diversified pertinent parameters on different flow fields. Besides, the influence of Casson and Williamson parameters were also displayed through streamlines and isotherms. However, this study investigated the fluid behavior of Lorentz force effects together with Nano-particle which increase the thermal conductivity of both fluids. The study has been done in two different phase of fluid flows. Finally, it was concluded that the mass and heat transform accomplishment of Williamson fluid was relatively lower compared to Casson fluid. The comparison was also done significantly through the updated visualisation of fluid flow in this study.

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Effects of aspect ratio on unsteady solutions through curved duct flow

Cited by 30 publications

References 22 publications

On the Onset of Hydrodynamic Instability with Convective Heat Transfer Through a Rotating Curved Rectangular Duct

On the Onset of Hydrodynamic Instability with Convective Heat Transfer Through a Rotating Curved Rectangular Duct

Numerical Prediction of Non-isothermal Flow with Convective Heat Transfer Through a Rotating Curved Square Channel with Bottom Wall Heating and Cooling from the Ceiling

MHD Radiative Flow of Casson and Williamson Nanofluids over an Inclined Cylindrical Surface with Chemical Reaction Effects

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