科研之友
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摘要
A direct numerical simulation of incompressible channel flow at a friction Reynolds number (Re-tau) of 5186 has been performed, and the flow exhibits a number of the characteristics of high-Reynolds-number wall hounded turbulent flows. For example, a region where the mean velocity has a logarithmic variation is observed, with von Karman constant K = 0.384 +/- 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.
- 出版日期2015-7
