The statistical properties of two-dimensional turbulent wake of a heated cylinder

By analyzing the experimental data, the statistical properties of 2D turbulent wake of a heated cylinder are studied. The coherent structures may have the stronger effect upon the transverse velocity and temperature than the longitudinal velocity. In the near wake, the transverse velocity v and the temperature T have the bimodal distribution and the χ2 distribution, respectively. But the distribution of the longitudinal velocity u is near the Gaussian even in the near wake. The statistical distributions for the velocity differences and the temperature differences are studied. In the near wake, the pdfs of the transverse velocity differences are concave functions only for the time separations nΔt:nc1<n<nc2. Otherwise, they will be the convex functions. The pdf of the temperature difference will change from the nearly exponential distribution to the Gaussian distribution as the time separation nΔt increasing in the near wake. Using the detrended fluctuation analysis, it is found out that the longitudinal velocity and temperature have the long-range correlation with the exponent α≈0.7 in the near and intermediate wake and the transverse velocity has the weakly anti-correlation with the exponent α≈0.44 in the intermediate wake.