Extended Data Figure 3: Determination of corresponding Reynolds numbers and speeds for pipe and duct flow.

a–d, Speeds from pipe (a, b) and duct flow (c, d) are plotted, as in Fig. 1c, but additionally with the upstream front speeds reflected about the neutral speed C₀. a, c, Experimental and simulation data only; b, d, model fits to the experimental and simulation data. The determined values for R₀, R₁, C₀ and C₁ are: R₀ = 1,920, C₀ = 1.06, R₁ = 2,250 and C₁ = 0.92 for pipe flow, and R₀ = 1,490, C₀ = 1.12, R₁ = 2,030 and C₁ = 0.90 for duct flow.