Seepage effects on settling velocity
Low, Stephanie Shui Yin
Date of Issue2017
School of Civil and Environmental Engineering
In research relating to sedimentology, marine or relatable industrial processes, a particle’s terminal velocity has been a key variable to analyse when studying its settling behaviour. Terminal velocity, which is also known as the settling velocity, is defined as the constant velocity achieved when the forces acting on a free falling object reaches equilibrium. The settling velocity is studied to analyse the behaviour of particles during sedimentation, suspension and sediment transportation. However, very little or no study has concerned the settling velocity of particles in the presence of an upward seepage. An upward seepage, also known as an injection, travels in the opposite direction of gravity. Hence, the objective of this report is to investigate how an injection affects the settling velocity of a spherical particle. In this investigation, the Reynolds number and drag coefficient were selected as a focal study to determine how seepage affects the settling velocity of the particle. This experimental set-up was conducted in a 1.07 m tall cylinder with an inlet, outlet and a valve which controls the rate of injection. The particles used for this experimental study consisted of four spheres with different densities and textures. A camera with a video recording function, capable of capturing up to 50 frames per second, was utilised to record the motion of each free-falling particle in the cylinder. The videos were able to observe and obtain the particle’s instantaneous settling velocity 0.04s interval. The results obtained from this report may be useful for researchers who want to analyse the behaviour of sediment transportation, industrial processes involving particle settling and in other related engineering fields.
Final Year Project (FYP)
Nanyang Technological University