Characteristics of Shallow Rain-Impacted Flow over Smooth Bed
Publication: Journal of Hydraulic Engineering
Volume 124, Issue 12
Abstract
An understanding of the effect of rainfall on the characteristics of shallow flow is needed for the proper modeling of the physical processes related to erosion and sedimentation. In this study, the turbulence characteristics of shallow rain-impacted flow over a smooth bed were investigated using a fiber-optic laser Doppler velocimeter and a specially designed artificial raindrop simulator. An empirical formula was derived to predict the variation of momentum correction factor β with the parameters related to the flow and the rainfall characteristics. Statistical correlations were developed successfully to predict the distributions of both the longitudinal and the vertical turbulence intensities for rainfalls with different intensities and raindrop diameters. The statistical characteristics of the Reynolds stress under different rainfall conditions also were analyzed. Analysis of the energy spectrum of the longitudinal velocity component indicated that the energy for the large-scale eddies (low frequencies) was increased significantly because of the mixing effect of the raindrop impact for the region near the water surface.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Bendat, J. S., and Piersol, A. G. (1986). Random data—analysis and measurement procedures. John Wiley & Sons, Inc., New York.
2.
Chang, F. H. (1996). “Turbulence characteristics of rain-impacted free surface flow,” MS thesis, National Chung-Hsing University, Taichung, Taiwan (in Chinese).
3.
Chien, N., and Wan, Z. H. (1983). Mechanics of sediment transport. Science Publication, Beijing, China (in Chinese).
4.
Daniels, H. E.(1954). “Saddlepoint approximation in statistics.”Ann. Math. Statistics, 32, 535–548.
5.
Daniels, H. E.(1987). “Tail probability approximations.”Int. Statistical Rev., 55, 37–48.
6.
Grass, A. J.(1971). “Structural features of turbulent flow over smooth and rough boundaries.”J. Fluid Mech., 50, 233–255.
7.
Hartley, D. M., and Julien, P. Y.(1992). “Boundary shear stress induced by raindrop impact.”J. Hydr. Res., Delft, The Netherlands, 30(3), 341–359.
8.
Hinze, J. O. (1975). Turbulence. McGraw-Hill, Inc., New York.
9.
Nikitin, N. K. (1963). “Turbulent flow and physical processes near channel boundary.” Ukraine National Science College Publication, Kiev, 142. (in Russian).
10.
Kisisel, I. I. T. (1971). “An experimental investigation of the turbulence characteristics of shallow water flow,” PhD dissertation, Purdue University, West Lafayette, Ind.
11.
Laufer, J. (1954). “Investigation of turbulence flow in a two dimensional channel.”Tech. Note No. 2123, National Advisory Committee for Aeronautics, Washington, D.C.
12.
Lu, J. Y., Foster, G. R., and Smith, R. E.(1987). “Numerical simulation of dynamic erosion in a ridge-furrow system.”Trans. ASAE, 30(4), 969–976.
13.
Lu, J. Y., and Wu, I. Y.(1992). “Simulation of rainfall and measurements of raindrop characteristics.”J. Chinese Soil and Water Conservation, 23(2), 1–12.
14.
Lugannani, R., and Rice, S.(1980). “Saddlepoint approximation for the distribution of the sum of independent random variables.”Adv. Appl. Probability, 12, 475–490.
15.
McQuivey, R. S., and Richardson, E. V.(1969). “Some turbulence measurements in open channel flow.”J. Hydr. Div., ASCE, 95(1), 209–223.
16.
Nezu, I., and Nakagawa, H. (1993). Turbulence in open-channel flows. A. A. Balkema Publishers, Brookfield, Vt.
17.
Nezu, I., and Rodi, W.(1986). “Open-channel flow measurements with a laser doppler anemometer.”J. Hydr. Engrg., ASCE, 112(5), 335–355.
18.
Shahabian, H. L., and Delleur, J. W. (1976). “An experimental investigation of the rainfall on the turbulence properties of overland flow.”Tech. Rep. No. 88, Water Resource Research Center, Purdue, University.
19.
Shen, H. W., and Lu, J. Y.(1983). “Development and prediction of bed armoring.”J. Hydr. Engrg., ASCE, 109(4), 611–629.
20.
Streeter, V. L., and Wylie, E. B. (1987). Fluid mechanics. McGraw-Hill, Inc., New York.
21.
Tan, S.(1990). “Rainfall and soil detachment.”J. Hydr. Res., 27(5), 699–715.
22.
Yoon, N. Y. (1970). “The effect of rainfall on the mechanics of steady spatially varied sheet flow on a hydraulically smooth boundary,” PhD dissertation, University of Illinois at Urbana-Champaign, Ill.
Information & Authors
Information
Published In
Copyright
Copyright © 1998 American Society of Civil Engineers.
History
Published online: Dec 1, 1998
Published in print: Dec 1998
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.