Uniform flow in a smooth open channel

Laboratory experiments on the structure of uniform flow in a smooth open channel are reported. Velocity profiles (Figs. 2 and 3) and turbulence intensity profiles (Fig. 6) as well as friction velocity (Table 2) were measured. It was found that: the universal law-of-the-wall describes rather well the data over the entire channel depth (Fig. 2); in the core of the outer region (0.2 < y/d < 0.7), a wake of limited strength (Π ≈ 0.08) exists; in the near-surface zone (0.7< y/d < 1.0), a retarding effect, possibly due to weak secondary currents, tends to compensate the wake divergence (Fig. 4), resulting in a modified distribution of the mixing length (Fig. 5).