scholarly journals Numerical Simulation of Rotating Turbulent Channel Flow by the Vortex in Cell Method

2013 ◽  
Vol 5 (1) ◽  
pp. 30-41 ◽  
Author(s):  
Tomomi Uchiyama
2015 ◽  
Vol 774 ◽  
pp. 395-415 ◽  
Author(s):  
Myoungkyu Lee ◽  
Robert D. Moser

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.


Author(s):  
Atsushi Sakurai ◽  
Koji Matsubara ◽  
Shigenao Maruyama

Importance of turbulence and radiation interaction (TRI) has been investigated in a turbulent channel flow by using direct numerical simulation (DNS) to clarify detailed turbulent flow structure and heat transfer mechanisms. To investigate the effect of correlation functions between gas absorption and temperature fluctuation, the two cases of correlation are tested. Consequently, the TRI effect can be clearly observed when the correlation is positive. This fact provides the evidence that radiative intensity is enhanced by the turbulent fluctuation. The DNS results suggest the significance in the fundamental aspect of TRI. Furthermore, effects of frictional Reynolds number, Reτ, are investigated. Comparing with the case of Reτ = 150, the location of the enhancement peaks of Reτ = 300 shifts toward the walls. It is found that the relative importance of the TRI correspond to the structure of temperature fluctuation intensity originated from the differences of the Reτ.


Author(s):  
Ali Reza Mazaheri ◽  
Goodarz Ahmadi ◽  
Haifeng Zhang

Effects of bounce on particle transport, deposition and removal in turbulent channel flow are studied. The pseudo-spectral method is used to generate the instantaneous turbulent fluid velocity field by Direct Numerical Simulation (DNS) procedure. The particle equation of motion includes all the relevant hydrodynamic forces. In addition, simulation accounts for particle adhesion, resuspension and rebound processes. For particle bounce from the surface, the critical velocity is evaluated and is used in the analysis. Effects of bounce during particle-wall collisions on the deposition rate are also studied.


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