Sand and Mud Properties

Oral

1296 - Revisiting The Role Of Aggregation In The Settling Of Cohesive Flocs In The Marine Environment

Presenting Author(s)

• AM

  Ashish Mehta, PhD

  Coastal Engineer
  Nutech Consultants, Inc.

Additional Author (s)

• WM

  William McAnally

Additional Author #2(s)

• FS

  Farzin Samsami

Additional Author #3(s)

• AM

  Andrew Manning

  
  HR Wallingford

The settling velocity is the most important property of cohesive flocs in the coastal environment. For the present purposes, time-dependent floc properties are represented by the floc diameter, density and shear strength. Aggregation, which includes floc growth and breakup due to collisions and shearing in turbulent flows, is modeled for flocs treated as fractal geometries. Based data from the Tamar estuary in UK, it is shown that the settling velocity depends on the time-history of the flow shear rate and the solids volume fraction. This observation is used to discuss a well-known analytic expression for estimating the settling velocity.