Figure 5.

(Colour online) Premultiplied streamwise ϕ₁₁ (a,d,g), wall-normal ϕ₂₂ (b,e,h) and spanwise ϕ₃₃ (c,f,i) two-dimensional velocity spectra at x₂/h = 0.10, 0.15, 0.20, 0.30 and 0.40 (from black to red) for NS2000. The wavelengths are scaled by h (a–c), x₂ (d–f) and l* (g–i). Contours are 0.1 and 0.6 of the maximum. The arrows in panels (a–c) indicate increasing distance from the wall.