V.A.Voskoboinick, V.T.Grinchenko, A.P.Makarenkov The velocities of convection of coherent vortex structures in a turbulent boundary layer on the cylinder |
Acoustic bulletin, Vol. 3 ¹ 4, (2000) |
| The experimental results are introduced on the phase and, also, the local and mean streamwise convective velocities of the pressure-producing correlation vortex structures of a turbulent boundary layer on the flexible extended cylinder streamlined by axialsymmetric flow. There are given the dependencies of convective velocities from the frequency, the Reynolds number Rex, and separations between transducers of pressure fluctuations. The comparative estimate of these convective velocities with the results for rigid cylinder, smooth and rough flat plates is yielded. The values of convective velocity are obtained from 0.6U∞ for small-scale high-frequency eddies up to velocity of the U∞ order for large-scale low-frequency vortex systems. It is found out that in a turbulent boundary layer on the flexible cylinder there exist the highly correlated vortex structures, which have higher convective velocity than in the cases of rigid cylinder and the plate. The increase of transverse curvature of surface of the streamlined cylinder d/a leads to saturation of boundary layer with large-scale pressure-producing vortex systems. |
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KEY WORDS: turbulence, boundary layer, correlated vortex structures, convective velocity |
| TEXT LANGUAGE: Russian |