Elliptic model for space-time correlations in turbulent shear flows.
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.
He
Guo-Wei
GW
LNM, Institute of Mechanics, Chinese Academy of Sciences, Beijing, People's Republic of China. hgw@lnm.imech.ac.cn
Zhang
Jin-Bai
JB