The Role of Turbulence on the Initiation of Sediment Movement

• Main Authors: Diplas, Panayiotis, Dancey, Clint L, Valyrakis, Manousos, Celik, Ahmet O, Greer, Krista
• Format: Conference Proceeding
• Language: English
• ISSN: 0094-243X
• DOI: 10.1063/1.3180093

Development of a criterion that determines accurately the onset of sediment movement in streams has been one of the major issues in fluvial hydraulics. In spite of the numerous works on this topic, the precise determination of such a criterion remains elusive. One of the main obstacles in developing a precise criterion is the fluctuating nature of turbulent flow, especially in the vicinity of a rough boundary. Though many researchers have advocated its important role in particle dislodgement, especially in flow conditions near threshold of movement, no approach has been able to account for its effects in a satisfactory way. The various methodologies that have been proposed to date are replete with inconsistencies. A new approach based on the concept of impulse rather than just force is proposed here in an effort to identify uniquely the conditions of initiation of motion. Experiments using electromagnetic forces to simulate turbulent pulses are used to demonstrate the validity of the new criterion.