Hydraulic resistances and capacity of uniform aerated and nonaerated rapid flows in concrete channels

Conclusions

• 1. Uniform rapid flows in concrete flumes, canals, and chutes, just as in smooth-walled and precast reinforced-concrete canals, obey an original law of hydraulic resistance, exressed by formula (4) with values of the constants K<0, w<0, z<0.

• 2. The indicated law of resistance and its analytical expression (4), which became known after publication of [2], are not taken into account by the recommendations on calculating the coefficients C or λ contained in current textbooks and standard references, which makes the latter unsuitable for calculating rapid flow in channels of the aforementioned categories.

• 3. For the example of concrete and smooth-walled channels in a wide range of slopes, the phenomenon of identity (v=idem) of the average velocities of the liquid phase of real aerated uniform rapid flows and hypothetical nonaerated flows in the same channels calculated by (4) for Q=idem was established.

• 4. The formula of the resistance coefficient (4) with parameters (10) and relation (16) of the aeration factor provide, with consideration of the identity of the velocities (v=idem) of the aerated and hypothetical nonaerated flows, a reliable calculation of aerated and nonaerated uniform rapid flows in concrete channels in a wide engineering range.

• 5. The hydraulic resistance coefficient and Chezy coefficient have practically constant values (24) in a wide region of uniform rapid flows in concrete industrial channels satisfying condition (23).