Hydraulic characteristics of countercurrent jets on adverse-sloped beds

Autor: Lei Wang, Zhen Li, Ming-jun Diao
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Water Supply, Vol 22, Iss 2, Pp 1876-1888 (2022)
Druh dokumentu: article
ISSN: 1606-9749
1607-0798
DOI: 10.2166/ws.2021.308
Popis: The counter-current jet (CCJ) acts like a reverse surface jet layer covering the free jump surface and has potential applications in the energy dissipation of hydraulic engineering. The present study investigated the hydraulic characteristics of CCJs on adverse-sloped beds. The results showed that, compared to the horizontal bed, the slope didn't increase the energy dissipation rate of CCJ but reduced the return flow length and upstream depth. The velocity distribution along the depth was divided into the boundary layer region, mixing region, and reverse surface jet region. The velocity distribution in the boundary layer region and the mixing region was similar to the classical wall jet. The jet Froude number and the bed slope had no significant effect on the turbulence intensity distribution and turbulence kinetic energy (TKE) distribution of CCJ. The distribution of TKE was similar to that of a submerged jump. The maximum absolute turbulence intensity appeared at exactly half of the maximum velocity. The maximum TKE appeared at the mixing region. Besides, empirical formulas for estimating length scales and maximum velocity attenuation are proposed. The results could provide a reference for the potential application of CCJ in energy dissipation in hydraulic engineering. HIGHLIGHTS The hydraulic characteristics of counter-current jets (CCJ) on adverse-sloped beds were investigated for the first time.; The velocity distribution of CCJ was divided into three regions along the depth.; The turbulence intensity and turbulence kinetic energy distribution of CCJ had self-similarity.; A new counter-current energy dissipator with potential applications was provided.;
Databáze: Directory of Open Access Journals
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