On the structure of wall-bounded turbulent flows

The variable-interval time-averaging (VITA) technique developed by Blackwelder and Kaplan J. Fluid Mech. 76, 89 (1976) is applied to data obtained from large-eddy simulation of turbulent channel flow in an investigation of the organized structures associated with the bursting phenomenon in the near-wall region. Conditionally averaged velocities, shear stress, pressure, and vorticity are discussed in conjunction with the bursting phenomenon detected by the VITA technique. The conditionally averaged pressure reveals that the ejection process is associated with a localized adverse pressure gradient. In the plane perpendicular to the flow direction, the conditionally averaged vorticity field indicates that a pair of counterrotating streamwise vortices is being lifted through the ejection process.