Turbulence and Shear Flow Phenomena -1 First International Symposium

ISBN Print: 1-56700-135-1

NEAR-WALL TURBULENCE STRUCTURES IN THREE-DIMENSIONAL BOUNDARY LAYERS

要約

In this study we examine the structure of near-wall turbulence in three-dimensional boundary layers (3DBLs), which we approximate by applying an impulsive spanwise motion to the lower wall of a turbulent channel flow. Direct numerical simulation (DNS) data are analyzed using Reynolds stress budgets, probability density functions (PDFs) and conditional-averaged quadrant analysis about strong sweeps and ejections, and visualization of vortices with the λ2 criterion. The evidence suggests that mean three-dimensionality breaks up the symmetry and alignment of near-wall structures, disrupting their 'self-sustaining mechanisms', and thereby causing a reduction in the turbulence kinetic energy (TKE).