Fully developed turbulent flow of non–Newtonian liquids through a square duct

Abstract Using multi-GPU in lattice Boltzmann method (LBM), fully developed turbulent flow in a square duct at the friction Reynolds numbers (Reτ) of 300, 600, 1200 and 1800 are simulated. Through simulation of three-dimensional lid-driven cavity flow under different Reynolds number (Re), the accuracy of lattice Bhatnager-Gross-Krook (LBGK) multi-GPU program is validated. For turbulent flow in a square duct, all mean velocity, secondary flows, root mean square (rms) of pulsating velocity and Reynolds shear stress predicted by LBGK under the lower Reτ agree well with the literature results, which further verified the effectiveness of the LBGK. In addition, fully developed turbulent flow in a square duct with Reτ up to 1800 predicted by LBGK with 600 million grids provides a reference for turbulent flows under high Reτ . Numerical results show that the LBGK model with low accuracy successfully captures turbulent characteristics for flows at high Re by increasing the grid size, indicating the feasibility and practicality of multi-GPU LBM for modeling industrial flows.

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THE NUMERICAL PREDICTION OF FULLY DEVELOPED TURBULENT FLOW AND HEAT TRANSFER IN A SQUARE DUCT WITH TWO ROUGHENED FACING WALLS

Proceeding of International Heat Transfer Conference 8 ◽

10.1615/ihtc8.1850 ◽

1986 ◽

Cited By ~ 1

Author(s):

Hideomi Fujita ◽

Hajime Yokosawa ◽

Chikayuki Nagata

Keyword(s):

Heat Transfer ◽

Turbulent Flow ◽

Numerical Prediction ◽

Square Duct ◽

Flow And Heat Transfer ◽

Fully Developed Turbulent Flow

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Enhanced secondary motion of the turbulent flow through a porous square duct

Journal of Fluid Mechanics ◽

10.1017/jfm.2015.623 ◽

2015 ◽

Vol 784 ◽

pp. 681-693 ◽

Cited By ~ 26

Author(s):

A. Samanta ◽

R. Vinuesa ◽

I. Lashgari ◽

P. Schlatter ◽

L. Brandt

Keyword(s):

Turbulent Flow ◽

Numerical Simulations ◽

Boundary Layers ◽

Stokes Equations ◽

Porous Wall ◽

Packed Bed ◽

Square Duct ◽

Fully Developed Turbulent Flow ◽

Porous Interface ◽

Flow Through

Direct numerical simulations of the fully developed turbulent flow through a porous square duct are performed to study the effect of the permeable wall on the secondary cross-stream flow. The volume-averaged Navier–Stokes equations are used to describe the flow in the porous phase, a packed bed with porosity ${\it\varepsilon}_{c}=0.95$. The porous square duct is computed at $\mathit{Re}_{b}\simeq 5000$ and compared with the numerical simulations of a turbulent duct with four solid walls. The two boundary layers on the top wall and porous interface merge close to the centre of the duct, as opposed to the channel, because the sidewall boundary layers inhibit the growth of the shear layer over the porous interface. The most relevant feature in the porous duct is the enhanced magnitude of the secondary flow, which exceeds that of a regular duct by a factor of four. This is related to the increased vertical velocity, and the different interaction between the ejections from the sidewalls and the porous medium. We also report a significant decrease in the streamwise turbulence intensity over the porous wall of the duct (which is also observed in a porous channel), and the appearance of short spanwise rollers in the buffer layer, replacing the streaky structures of wall-bounded turbulence. These spanwise rollers most probably result from a Kelvin–Helmholtz type of instability, and their width is limited by the presence of the sidewalls.

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