title: Elliptic model for space-time correlations in turbulent shear flows.
abstract: An elliptic model for space-time correlations in turbulent shear flows is proposed based on a second order approximation to the iso-correlation contours, while Taylor's hypothesis implies a first-order approximation. It is shown that the space-time correlations are mainly determined by their space correlations and the convection and sweeping velocities. This model accommodates two extreme cases: Taylor's hypothesis at vanishing sweeping velocity and the sweeping hypothesis at vanishing convection velocity. The result is supported by the data from the direct numerical simulation of turbulent channel flows.
authors.affiliation: LNM, Institute of Mechanics, Chinese Academy of Sciences, Beijing, People's Republic of China. hgw@lnm.imech.ac.cn
authors.forename: Guo-Wei
authors.initials: GW
authors.lastname: He
authors.forename: Jin-Bai
authors.initials: JB
authors.lastname: Zhang