Direct Numerical Simulation of Turbulent Channel Flow With Streamwise System-Rotation

2015 ◽  
Author(s):  
Masayoshi Okamoto
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Direct Numerical Simulation ◽  
High Reynolds Number ◽  
Turbulent Channel Flow ◽  
Quadrant Analysis ◽  
Mean Velocity ◽  
Reynolds Number Flow ◽  
High Reynolds ◽  
Low Speed Streaks

The direct numerical simulation (DNS) of the fully developed turbulent channel flows rotating along the streamwise direction with several rotation parameters and two Reynolds numbers is performed. The bulk mean velocity decreases with increasing the rotation parameter, but the decrement is weakened in the high Reynolds number case. Applying the second-kind Chebyshev polynomial expansion into the mean spanwise velocity, the second mode coefficient, which becomes large in the strong rotation, is greatly influenced by the Reynolds number effect. Due to the streamwise rotation, the derivative and integral length scales obtained from the streamwise two-point correlation are extended. From viewpoints of the quadrant analysis, spectral one and instantaneous visualization, the high correlation among three fluctuating velocity components appears and the low-speed streaks are accumulated in the strong rotation and high Reynolds number flow.

Direct numerical simulation of turbulent channel flow up to

2015 ◽  
Vol 774 ◽  
pp. 395-415 ◽  
Author(s):  
Myoungkyu Lee ◽  
Robert D. Moser
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Direct Numerical Simulation ◽  
Turbulent Flows ◽  
Channel Flow ◽  
Turbulent Channel Flow ◽  
Streamwise Velocity ◽  
Mean Velocity ◽  
Layer Structures ◽  
High Reynolds

A direct numerical simulation of incompressible channel flow at a friction Reynolds number ($\mathit{Re}_{{\it\tau}}$) of 5186 has been performed, and the flow exhibits a number of the characteristics of high-Reynolds-number wall-bounded turbulent flows. For example, a region where the mean velocity has a logarithmic variation is observed, with von Kármán constant ${\it\kappa}=0.384\pm 0.004$. There is also a logarithmic dependence of the variance of the spanwise velocity component, though not the streamwise component. A distinct separation of scales exists between the large outer-layer structures and small inner-layer structures. At intermediate distances from the wall, the one-dimensional spectrum of the streamwise velocity fluctuation in both the streamwise and spanwise directions exhibits $k^{-1}$ dependence over a short range in wavenumber $(k)$. Further, consistent with previous experimental observations, when these spectra are multiplied by $k$ (premultiplied spectra), they have a bimodal structure with local peaks located at wavenumbers on either side of the $k^{-1}$ range.

0507 Peta-Scale Direct Numerical Simulation of Wall Turbulence at High Reynolds Number by K computer

2013 ◽  
Vol 2013 (0) ◽  
pp. _0507-01_-_0507-02_
Author(s):  
Naoya FUKUSHIMA ◽  
Kazuaki TOKUMARU ◽  
Hiroya MAMORI ◽  
Kaoru IWAMOTO ◽  
Koji FUKAGATA ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Direct Numerical Simulation ◽  
High Reynolds Number ◽  
Wall Turbulence ◽  
High Reynolds
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