کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1896496 | 1044435 | 2010 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Statistics of velocity gradients in wall-bounded shear flow turbulence Statistics of velocity gradients in wall-bounded shear flow turbulence](/preview/png/1896496.png)
The statistical properties of velocity gradients in a wall-bounded turbulent channel flow are discussed on the basis of three-dimensional direct numerical simulations. Our analysis is concentrated on the trend of the statistical properties of the local enstrophy ω2(x,t) and the energy dissipation rate ϵ(x,t) with increasing distance from the wall. We detect a sensitive dependence of the largest amplitudes of both fields (which correspond with the tail of the distribution) on the spectral resolution. The probability density functions of each single field as well as their joint distribution vary significantly with increasing distance from the wall. The largest fluctuations of the velocity gradients are found in the logarithmic layer. This is in agreement with recent experiments which observe a bursting of hairpin vortex packets into the logarithmic region.
Journal: Physica D: Nonlinear Phenomena - Volume 239, Issue 14, 15 July 2010, Pages 1258–1263