IAHR, founded in 1935, is a worldwide independent member-based organisation of engineers and water specialists working in fields related to the hydro-environmental sciences and their practical application. Activities range from river and maritime hydraulics to water resources development and eco-hydraulics, through to ice engineering, hydroinformatics, and hydraulic machinery.
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You are here : eLibrary : IAHR World Congress Proceedings : 32nd Congress - Venice (2007) : THEME B: Data Acquisition and Processing For Scientific Knowledge and Public Awareness. : Physical modeling of sheet flow on highway pavement surfaces
Physical modeling of sheet flow on highway pavement surfaces
Author : Randall J. Charbeneau , Jaehak Jeong , Emily Reeder , Wa Seong Chan
Curved highway segments often use superelevation to help balance centrifugal forces on vehicles. Superelevation transitions have regions with near-zero cross-slope which may promote extended stormwater drainage paths on the pavement surfaces, increasing ponding depth, splash from vehicles, and the potential for hydroplaning. The overall objective of this research project is to develop design guidance on minimum longitudinal grade through superelevation transitions. This manuscript presents results from an experimental study of sheet flow characteristics on rough surfaces under simulated rainfall conditions. A large-scale (13 meter) experimental facility was developed. A rainfall simulator, with its unique rotating system, provides uniform rainfall on the roadway model surface. The roadway model is coated by resin with sand particles to simulate the roughness of asphalt and concrete type pavement surfaces. The support system of the roadway model was constructed as to allow variation of the surface slope. To describe the hydraulics of sheet flow on pavement surfaces, a model for the Manning coefficient is developed and evaluated. Because the pavement roughness is relatively large compared with the thickness of sheet flow, the shear drag, often represented by the friction slope, needs to be defined carefully. The proposed model shows that the roughness coefficient should be larger for low Reynolds number but asymptotically approaches to a constant value as flow rate increases. Furthermore, we observed that the impact of rainfall on the flow resistance for rough surfaces is negligible compared to surface
drag.
File Size : 301,249 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 32nd Congress - Venice (2007)
Article : THEME B: Data Acquisition and Processing For Scientific Knowledge and Public Awareness.
Date Published : 01/07/2007
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