Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Application of Displacement Height and Surface Roughness Length to Determination Boundary Layer Development Length over Stepped Spillway
One of the most uncertain parameters in stepped spillway design is the length (from the crest) of boundary layer development. The normal velocity profiles responding to the steps as bed roughness are investigated in the developing non-aerated flow region. A detailed analysis of the logarithmic vertical velocity profiles on stepped spillways is conducted through experimental data to verify the computational code and numerical experiments to expand the data available. To determine development length, the hydraulic roughness and displacement thickness, along with the shear velocity, are needed. This includes determining displacement height d and surface roughness length z0 and the relationship of d and z0 to the step geometry. The results show that the hydraulic roughness height ks is the primary factor on which d and z0 depend. In different step height, step width, discharge and intake Froude number, the relations d/ks = 0.22–0.27, z0/ks = 0.06–0.1 and d/z0 = 2.2–4 result in a good estimate. Using the computational code and numerical experiments, air inception will occur over stepped spillway flow as long as the Bauer-defined boundary layer thickness is between 0.72 and 0.79.
Application of Displacement Height and Surface Roughness Length to Determination Boundary Layer Development Length over Stepped Spillway
One of the most uncertain parameters in stepped spillway design is the length (from the crest) of boundary layer development. The normal velocity profiles responding to the steps as bed roughness are investigated in the developing non-aerated flow region. A detailed analysis of the logarithmic vertical velocity profiles on stepped spillways is conducted through experimental data to verify the computational code and numerical experiments to expand the data available. To determine development length, the hydraulic roughness and displacement thickness, along with the shear velocity, are needed. This includes determining displacement height d and surface roughness length z0 and the relationship of d and z0 to the step geometry. The results show that the hydraulic roughness height ks is the primary factor on which d and z0 depend. In different step height, step width, discharge and intake Froude number, the relations d/ks = 0.22–0.27, z0/ks = 0.06–0.1 and d/z0 = 2.2–4 result in a good estimate. Using the computational code and numerical experiments, air inception will occur over stepped spillway flow as long as the Bauer-defined boundary layer thickness is between 0.72 and 0.79.
Application of Displacement Height and Surface Roughness Length to Determination Boundary Layer Development Length over Stepped Spillway
Xiangju Cheng (Autor:in) / John S. Gulliver (Autor:in) / Dantong Zhu (Autor:in)
2014
Aufsatz (Zeitschrift)
Elektronische Ressource
Unbekannt
Metadata by DOAJ is licensed under CC BY-SA 1.0
Air-water Surface Roughness in Self-Aerated Stepped Spillway Flows
| British Library Conference Proceedings | 2013
Stepped Spillway Downstream of a Piano Key Weir – Critical Length for Uniform Flow
| HENRY – Bundesanstalt für Wasserbau (BAW) | 2013
Stepped Spillway Downstream of a Piano Key Weir – Critical Length for Uniform Flow
| BASE | 2013
Converging stepped spillway flow
| Taylor & Francis Verlag | 2016
| British Library Conference Proceedings | 2000