The size of turbulent eddies close to a wall

Coherent flow‐oriented structures, with a dimensionless spacing of λ + ≈ 100, observed close to a wall in turbulent flows are believed to control the production of turbulence. A 2 1/2 D computer model developed by Nikolaides is used to explain the dimensionless spacing of these structures. The calculations suggest that the net production of turbulence in the viscous wall region is sensitive to changes in λ + in the neighborhood of λ + ≈ 100. They indicate that the net production is negative for λ + < 85 and that for λ + = 93 the net production is large enough to supply the turbulent energy dissipated in the outer flow.