Record Display for the EPA National Library Catalog


OLS Field Name OLS Field Data
Main Title Effect of Raindrop Impact and Surface Roughness on Sheet Flow.
Author Wenzel, J, Harry G. ;
CORP Author Illionis Univ., Urbana. Water Resources Center.
Year Published 1970
Report Number WRC-RR-34; DI-14-01-0001-1499; OWRR-B-018-ILL; 03310,; B-018-ILL(3)
Stock Number PB-196 664
Additional Subjects ( Surface water runoff ; Raindrops) ; ( Raindrops ; Water impingement) ; ( Surface roughness ; Surface water runoff) ; Water flow ; Sheet flow
Library Call Number Additional Info Location Last
NTIS  PB-196 664 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. 06/23/1988
Collation 126p
An experimental and analytical study was conducted to investigate the mechanics of sheet flow as it is affected by rainfall. Water surface profile data were taken in a laboratory flume using artificially generated rainfall and a hydraulically smooth surface. The one-dimensional spatially varied flow equation as developed from the momentum approach was then used to compute the boundary shear stress and subsequently a Weisbach type friction factor. Turbulence intensity measurements indicate that turbulence is generated at the surface due to the rainfall and also at the boundary for flow which would normally be laminar without rainfall. Spectral analysis of the turbulent measurements indicates that the rainfall shifts the turbulent energy to higher frequencies than would be the case without rainfall. Analysis of the flow over rough surfaces taken by the Corps of Engineers shows that rainfall has little effect on resistance beyond the transition region and the transition point may be lowered by the presence of rainfall. A separate study of a single drop striking a stagnant water layer shows that the velocity and pressure field can be computed using a Synthetic-Cell-Fluid scheme to solve the Navier-Stokes equations for this case. A dimensionless maximum impact pressure model was developed and the velocity field and free surface configuration were studied. It was found that surface tension is significant, the diameter of the region of disturbance was approximately one inch, and that locally high shear stress are generated. These stresses could easily cause soil erosion. (Author)