Development of Bed Configurations in Coarse Sands.
MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF EARTH AND PLANETARY SCIENCES
Pagination or Media Count:
Flume experiments were conducted with five coarse sands of different sizes to investigate the development of bed configurations. For fixed depth and increasing velocity the bed configurations are no movement, flat bed, ripples, bars, and dunes. For sand sizes coarser than about 0.70 mm, ripples are replaced by a flat bed. By introducing an irregularity on the sediment bed, ripples can be initiated in the no-movement and flat-bed phases. Ripples develop because of the effect of turbulence on the bed in the reattachment zone. The resulting strong instantaneous shear stresses initiate a maximum in sediment transport, which generates a ripple. The sequence ripples to bars to dunes observed in the experiments matches that observed in rivers and in the ocean. Modified author abstract
- Physical and Dynamic Oceanography
- Geology, Geochemistry and Mineralogy
- Civil Engineering
- Fluid Mechanics