Air-Water Flows and Head Losses on Stepped Spillways with Inclined Steps

Yvan Arosquipa Nina, Rui Shi, Davide Wüthrich, Hubert Chanson*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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On a stepped spillway, the staircase invert profile generates some intense turbulent dissipation during the spill, associated with a significant reduction of kinetic energy, as well as strong self-aeration. The present study focused on the effects of inclined downward steps on the air-water flow properties, flow resistance, and head losses because these mostly relate to spillway design. Some physical modeling was conducted in a relatively large facility with a 45° stepped chute (1V:1H) operating with Reynolds numbers 2.8×103<Re<1×106. The presence of downward steps induced some elongated asymmetrical cavity shapes, creating a less stable cavity recirculation pattern along the entire chute, leading to different interactions with the main stream. In terms of basic air-water flow properties, the distributions of void fraction and bubble count rate presented very close results for all three stepped geometries, both qualitatively and quantitatively. The interfacial velocities did not reach any uniform equilibrium (i.e., normal flow) condition, and the fastest velocities were recorded with the 1V:2.33H inclined downward stepped chute geometry (δ =23.3° and λ/k=3), and the slowest velocities on the horizontal stepped chute (δ=0 and λ/k=2). The Darcy-Weisbach friction factor f and relative head loss δ H/Hmax were estimated in the self-aerated flow. The comparative analyses suggested that the largest total drag and head losses were observed on the stepped chute with flat horizontal steps. An inclined downward stepped design yielded lesser head losses for all investigated flow conditions, providing an important information for practical engineers designing these hydraulic structures.

Original languageEnglish
Article number04022037
Number of pages15
JournalJournal of Irrigation and Drainage Engineering
Issue number11
Publication statusPublished - 2022

Bibliographical note

Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the
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  • Air-water flows
  • Head losses
  • Inclined steps
  • Physical modeling
  • Stepped spillways


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