Pressure fluctuations on the bottom of open-channel turbulent flows in spillway structures

Conclusion

Comparing the results of the prototype and model investigations, we can state that pressure fluctuations on the bottom of a gradually varied and markedly nonuniform flow (hydraulic jump) are reproduced sufficiently well on models of the structures, and the slight distortions of the energy-frequency spectrum caused by the nonmodelability of aeration and microturbulence of the flow can be disregarded. If it is necessary to conduct dynamic calculations of the structures, when a rigorous and spectrum-differentiated consideration of the pressure fluctuations is required, corrections obtained on the basis of the examined investigations (Fig. 3a, c) can be introduced.

The intensity of the pressure fluctuations on the bottom of the flow under the free-falling flow under prototype conditions compared to the model data noticeably decreases due to aeration and fragmentation of the flow, which for all practical purposes are not reproduced in the model. When converting the data from the model to the prototype the correction factors given in Fig. 2 and Fig. 3b can be used as the first approximation in the investigated case. It is necessary to continue investigations of this problem.