Investigation of Large Scale Motion Interaction with the Near‐Wall Turbulence

Abstract

AbstractThe main objective of the current work is to better understand the interaction of pipe flow large‐scale structures in the outer region with the near‐wall turbulence. To do so, a decomposition of velocity fluctuating signals has been adopted. Thus, the streamwise velocity fluctuation has been measured for three Reynolds numbers using two pipes located at the Brandenburg University of Technology (BTU). Three Reynolds numbers, Reb ≈ 6 × 104, Reb ≈ 105 and at Reb ≈ 6 × 105, have been examined, where Reb is the Reynolds number based on the bulk velocity (Ub), the pipe diameter (D) and the kinematic viscosity (ν). For both pipe facilities, constant temperature hot‐wire anemometry has been utilized. The comparison of those three cases addresses the low and high Reynolds number effects on the structures of the outer and the inner regions of the pipe flow. Subsequently, Reynolds‐number scaling for such structures and their interaction with the buffer‐layer turbulence will be examined.