Effects of the Reynolds number on the mean skin friction decomposition in turbulent channel flows

2019 ◽  
Vol 40 (3) ◽  
pp. 331-342 ◽  
Author(s):  
Yitong Fan ◽  
Cheng Cheng ◽  
Weipeng Li
Keyword(s):  
Reynolds Number ◽  
Skin Friction ◽  
Channel Flows ◽  
Turbulent Channel Flows ◽  
The Mean

Decomposition of the mean skin-friction drag in compressible turbulent channel flows

2019 ◽  
Vol 875 ◽  
pp. 101-123 ◽  
Author(s):  
Weipeng Li ◽  
Yitong Fan ◽  
Davide Modesti ◽  
Cheng Cheng
Keyword(s):  
Heat Flux ◽  
Mach Number ◽  
Skin Friction ◽  
Wall Layer ◽  
Channel Flows ◽  
Wall Heat Flux ◽  
Generation Process ◽  
Friction Drag ◽  
Turbulent Channel Flows ◽  
The Mean

The mean skin-friction drag in a wall-bounded turbulent flow can be decomposed into different physics-informed contributions based on the mean and statistical turbulence quantities across the wall layer. Following Renard & Deck’s study (J. Fluid Mech., vol. 790, 2016, pp. 339–367) on the skin-friction drag decomposition of incompressible wall-bounded turbulence, we extend their method to a compressible form and use it to investigate the effect of density and viscosity variations on skin-friction drag generation, using direct numerical simulation data of compressible turbulent channel flows. We use this novel decomposition to study the skin-friction contributions associated with the molecular viscous dissipation and the turbulent kinetic energy production and we investigate their dependence on Reynolds and Mach number. We show that, upon application of the compressibility transformation of Trettel & Larsson (Phys. Fluids, vol. 28, 2016, 026102), the skin-friction drag contributions can be only partially transformed into the equivalent incompressible ones, as additional terms appear representing deviations from the incompressible counterpart. Nevertheless, these additional contributions are found to be negligible at sufficiently large equivalent Reynolds number and low Mach number. Moreover, we derive an exact relationship between the wall heat flux coefficient and the skin-friction drag coefficient, which allows us to relate the wall heat flux to the skin-friction generation process.

GS11 Transient Phenomena in Turbulent Channel Flows by Sudden Changes of Reynolds Number

2015 ◽  
Vol 2015 (0) ◽  
pp. _GS11-1_-_GS11-5_
Author(s):  
Tomohiro SASAKI ◽  
Masayoshi OKAMOTO
Keyword(s):  
Reynolds Number ◽  
Channel Flows ◽  
Transient Phenomena ◽  
Turbulent Channel Flows

Vorticity transport in low Reynolds number turbulent channel flows

2016 ◽  
Vol 55 ◽  
pp. 272-278 ◽  
Author(s):  
Sedat Tardu ◽  
Frédéric Bauer
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Channel Flows ◽  
Turbulent Channel Flows ◽  
Low Reynolds ◽  
Vorticity Transport

scholarly journals The Role of Forcing and Eddy Viscosity Variation on the Log-Layer Mismatch Observed in Wall-Modeled Large-Eddy Simulations

2018 ◽  
Vol 141 (5) ◽  
Author(s):  
Rey DeLeon ◽  
Inanc Senocak
Keyword(s):  
Flow Rate ◽  
Eddy Viscosity ◽  
Degree Of Freedom ◽  
Channel Flows ◽  
Momentum Balance ◽  
Mean Velocity ◽  
Turbulent Channel Flows ◽  
The Mean ◽  
Viscosity Variation

We investigate the role of eddy viscosity variation and the effect of zonal enforcement of the mass flow rate on the log-layer mismatch problem observed in turbulent channel flows. An analysis of the mean momentum balance shows that it lacks a degree-of-freedom (DOF) when eddy viscosity is large, and the mean velocity conforms to an incorrect profile. Zonal enforcement of the target flow rate introduces an additional degree-of-freedom to the mean momentum balance, similar to an external stochastic forcing term, leading to a significant reduction in the log-layer mismatch. We simulate turbulent channel flows at friction Reynolds numbers of 2000 and 5200 on coarse meshes that do not resolve the viscous sublayer. The second-order turbulence statistics agree well with the direct numerical simulation benchmark data when results are normalized by the velocity scale extracted from the filtered velocity field. Zonal enforcement of the flow rate also led to significant improvements in skin friction coefficients.

Effect of nonisothermal conditions of skin friction in subsonic turbulent channel flows

1984 ◽  
Vol 25 (1) ◽  
pp. 63-68
Author(s):  
D. I. Lamden ◽  
I. L. Mostinskii ◽  
M. B. Reznikov
Keyword(s):  
Skin Friction ◽  
Channel Flows ◽  
Turbulent Channel Flows ◽  
Nonisothermal Conditions
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