Abstract
The propagation speed of the streamwise velocity fluctuations in turbulent channel flows is calculated using direct numerical simulation (DNS) data at four Mach numbers (, , , and ). The profiles of are shown to display remarkable similarity at different . 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 . 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.
- Received 4 April 2012
DOI:https://doi.org/10.1103/PhysRevE.86.046307
©2012 American Physical Society