Effect of sediment size distribution on bed elevation variation

• Main Author: Tan, Petrina
• Other Authors: Cheng Niansheng
• Format: Final Year Project
• Language: English
• Published: 2016
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/68615
• Institution: Nanyang Technological University

The type of river flow affects the elevation variation of rough open channels. Broadly, river flows can be classified into steady flow versus unsteady flow and uniform flow versus non-uniform flow when subjected to time and space as a criterion respectively. Regardless of the type of flow, there is bound to be constant movement of the sediments on the river bed. This study aims to investigate the relationship between the degree of river flow and river bed elevation through a series of vibration tests subjected to man-made bed conditions. In present work, controlled varying amplitudes will be used to stimulate the extent of the river flow. Additionally, a technique of using mixed compositions of sediment sizes will be used to enact differing river beds. The results demonstrate that a moderate flow may produce the most “smooth” bed elevation while the others generates an increasing disordered bed elevation. This study uses several roughness parameters to assess the surface roughness of the “river bed” and discusses the effect of the degree of roughness. However, to reconcile the relations for artificial and natural roughness completely, it may be necessary to further consider the contribution to flow resistance made by roughness shape and background roughness.