Direct numerical simulation of a fully developed turbulent square duct flow up to Reτ=1200Reτ=1200

• DNS on turbulent duct flows was conducted up to Reτ=1200Reτ=1200.
• Cartesian staggered meshes were employed up to 167.8 millions.
• Both the mean flow and turbulent statistics are affected by ReτReτ.
• The mesh resolution is critical to predict the flow quantities correctly.

Various fundamental studies based on a turbulent duct flow have gained popularity including heat transfer, magnetohydrodynamics as well as particle-laden transportation. An accurate prediction on the turbulent flow field is critical for these researches. However, the database of the mean flow and turbulence statistics is fairly insufficient due to the enormous cost of numerical simulation at high Reynolds number. This paper aims at providing available information by conducting several Direct Numerical Simulations (DNS) on turbulent duct flows at Reτ=300,600,900and1200. A quantitative comparison between current and previous DNS results was performed where a good agreement was achieved at Reτ=300Reτ=300. However, further comparisons of the present results with the previous DNS results at Reτ=600Reτ=600 obtained with much coarser meshes revealed some discrepancies which can be explained by the insufficient mesh resolution. At last, the mean flow and turbulent statistics at higher ReτReτ was presented and the effect of ReτReτ on the mean flow and flow dynamics was discussed.

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