摘要:

The propagation speed Vc of the streamwise velocity fluctuations u' in turbulent channel flows is calculated using direct numerical simulation (DNS) data at four Mach numbers (M=0, 0.8, 2.0, and 3.0). The profiles of Vc are shown to display remarkable similarity at different M. Quantitative models are developed based on a statistical structure called Velocity-Vorticity Correlation Structure (VVCS), defined as the vorticity region most correlated to velocity fluctuations at a fixed location. Good agreement with DNS-measured propagation velocities is obtained throughout the channel and for all M. The result confirms earlier speculation that the near-wall propagation is due to an advection by coherent vortex structures, and validates the concept of the VVCS.

附注:

Pei, JChen, JShe, Z-SHussain, FengResearch Support, Non-U.S. Gov'tPhys Rev E Stat Nonlin Soft Matter Phys. 2012 Oct;86(4 Pt 2):046307. doi: 10.1103/PhysRevE.86.046307. Epub 2012 Oct 10.