Study of fluctuating pressures over a steep stepped spillway


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Date

2024

Publication Type

Conference Paper

ETH Bibliography

no

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Abstract

A numerical study of instantaneous pressures at points of interest in the non-aerated region of a steep stepped spillway was performed, for which very recent experimental measurements exist from a physical model. The objective is to compare the experimental fluctuating pressures measured on the horizontal step treads with a computational model capable of collecting instantaneous flow pressure data. The chosen hydraulic model is a stepped spillway with 60 steps, with a slope of 0.75H:1V (53.13°). The employed unit discharge was 0.5 m2/s (q), which corresponds to a dimensionless critical depth (yc/h) of 4.9 and a Reynolds number of approximately 5x105. Under these conditions, the observed air entrainment point in the experiments was located approximately at step 31. The implemented numerical model includes a portion of the same geometry as the experimental model. Comparison of experimental and computed values of mean, instantaneous and fluctuating pressures was undertaken in the non-aerated region, between steps 5 to 30, at 8 mm from the solid edges of the steps, following the same methodology as the experimental study. Overall, the numerical model reproduces the trends in mean values of these variables quite well; however, it overestimates turbulent fluctuations. This causes more extreme negative pressures than those reported in experiments and lower positive peak pressures. Our numerical implementation constitutes a first step towards implementing tools to predict instantaneous pressures in the non-aerated region of steep stepped spillways.

Publication status

published

External links

Book title

Proceedings of the 10th International Symposium on Hydraulic Structures (ISHS 2024)

Journal / series

Volume

Pages / Article No.

105 - 112

Publisher

ETH Zurich

Event

10th International Symposium on Hydraulic Structures (ISHS 2024)

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

Stepped spillway; non-aerated flow region; instantaneous pressure; fluctuating pressure

Organisational unit

03820 - Boes, Robert / Boes, Robert check_circle

Notes

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