# International Association for Hydro-Environment Engineering and Research

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.
 You are here : eLibrary : IAHR World Congress Proceedings : 35th IAHR Congress - Chengdu (2013) : THEME 5 - FLUVIAL HYDRAULICS AND RIVER MANAGEMENT : The Nonlinear Cusp-catastrophe Model of Incipient Motion for Non-uniform Sediment
 The Nonlinear Cusp-catastrophe Model of Incipient Motion for Non-uniform Sediment Author : Jurui Yang, Xiaoxia Hou, Hui Li, Shuyou Cao and Xingnian Liu The cusp-catastrophe theory of nonlinear science is applied for studying sediment incipient motion in this paper. The state variables and the bound variables in cusp-catastrophe model have been found by analyzing the factors of sediment incipient motion, and the cusp-catastrophe model which used to reflect the sediment incipient motion has been built. Based on the standard equation of the cusp-catastrophe, the relation formula between Shields number and Reynolds number of sediment has been derived by using coordinate transform and topology transform. The Shields number is regarded as the state variable, and negative 0.3 power Reynolds number of sediment and zero dimension number md \d are regarded as the bound variable in the cusp-catastrophe model. Sink experimental data m 0 verified the function relationship between flow shear stress t and particle size d of incipient motion. The 0 0 verification results show that the calculated value agrees well with the sink experimental result. When d is larger, 0 the error is between 1% 30%, which is small. While the particle size d is smaller, the error is larger; the maximum 0 error is 76.2%. This indicates that the cusp-catastrophe formula is reasonable, and the results fully reflect the characteristics of threshold motion of non-uniform sediment. The purpose of this paper is to explore the incipient motion laws of non-uniform sediment from the viewpoint of nonlinear science. File Size : 278,088 bytes File Type : Adobe Acrobat Document Chapter : IAHR World Congress Proceedings Category : 35th IAHR Congress - Chengdu (2013) Article : THEME 5 - FLUVIAL HYDRAULICS AND RIVER MANAGEMENT Date Published : 18/07/2016 Download Now