Ingénierie /Agriculture
Irrigation et Drainage Gestion
Description
Le hydraulics de flow en le irrigation et drainage channels is indeed complex pour many reasons en natural conditions. Such channels are required to carry a certain specified discharge de water which is charged avec sediment load de suspended et bed material. Le boundaries de le channel are thus en a state de constant flux. Bed et banks, although initially flat surfaces, may soon be covered avec ripples et dunes. These are en effect large elements de surface roughness having a strong influence sur le overall channel friction. Stability de these channels is defined as a state de equilibrium such that le particles sur le surface de such channels are en a critical condition de movement. Un channel shape which ensures that le particles everywhere sur le channel surface are subjected to a resultant boundary stress which equals le critical shear stress is a stable profile. When le capacity pour transporting sediment de a channel is equal to le time rate de sediment supply at its head, it is said to be a stable channel. Stable channels are also sometimes called regime channels. Recent empirical et theoretical work sur irrigation channels suggests en natural form that instability is inherent. Un occurrence de multiple cut-offs at river meanders could be interpreted as a clustering associated avec self-organized criticality. Types de meander behaviour ranging from stable to chaotic are examined as trajectories or attractors within le phase space de rate de meander movement et bend curvature et change to le system is explored as shift from one attractor to another. It is suggested that this new approach provides insights into meander dynamics et provides a basis to identify le conditions, limits et constraints under which different behaviour occurs. Meanders have been subject to much analysis, de various kinds, en fluvial geomorphology because de their remarkable forms, their dynamism et le practical consequences de their movement. Le aim de this book is to examine evidence de complex behaviour at natural irrigation et drainage boundaries, and, en particular, possible operation de self-organized criticality en meandering systems, using primary evidence de a field study et also evidence from a kinematic model.
Table des matières
Natural Irrigation et Drainage, Regime Théorie, Empirical Correlation et Regression Théorie, Tractive Force Théorie, Threshold Channel Geometry Théorie, Similarity Principle; Section 3, Minimum Variance Théorie, Threshold Channel Geometry Théorie (Downstream Section, Maximum Sediment Discharge Théorie (White et al.’s Work): Derivation de Hydraulic Geometry; Hypothesis, Maximum Sediment Discharge et Froude Number, Bedform Migration, Braided River, Chapter. Meander Theories, Meandering Boundary Layers, Modelling width Adjustment en Meandering Channels, Hydraulic Geometry Relations Using Du Boys Type Bed Load Formulae, Hypothesis de Maximum Friction Factor (Davies et al. Work), Minimal Channel Mobility Théorie, Hydrodynamical Théorie, Thermodynamic Théorie, Minimum Énergie Dissipation Rate Théorie, Entropy Théorie, Fluvial Process Hydraulic Geometry Relations