Modeling Scour Downstream of a Levee Using Flow-3D

Document Type : Research Paper

Authors

Faculty of Civil Engineering, University of Zanjan, Zanjan, Iran

Abstract

In this paper, the results of numerical modeling of water flow over a dam and the depth and length of the downstream scour hole are compared with the experimental results of Muhammad Abbas and Tanaka under different hydraulic conditions including two critical depths on the spillway crest (Dc) equal to 0.03 and 0.04 m and two downstream depths (Dp) of 0.07 and 0.09 m. For this purpose, the dimensionless parameters of the flow depths on the crest and downstream, namely Dc*=Dc/HE and Dp*=Dp/HE, have been used. Also, the dimensionless parameters Sd*=Sd/HT and Ls*=Ls/HT have been used for the scour depth and scour hole length. With increasing the dimensionless downstream depth (Dp*), it was observed that with increasing Dc* and correspondingly the critical flow depth on the spillway crest, the maximum depth and length of the scour hole increase, but with increasing the dimensionless critical depth Dc*, these values ​​decrease. On average, the difference between the numerical and experimental results is less than 3/75%. It can be concluded that there is a good agreement between the results. Numerical simulation of physical phenomena allows for a more detailed study of the flow field, velocity vectors, and pressure contours, which is also discussed in this article.

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