Multimodal particle size distributions of fine-grained sediments: mathematical modeling and field investigation
Lee, B.J.; Toorman, E.; Fettweis, M. (2014). Multimodal particle size distributions of fine-grained sediments: mathematical modeling and field investigation. Ocean Dynamics 64(3): 429-441. dx.doi.org/10.1007/s10236-014-0692-y In: Ocean Dynamics. Springer-Verlag: Berlin; Heidelberg; New York. ISSN 1616-7341; e-ISSN 1616-7228, more |  |
| Keyword | | | Author keywords | Cohesive sediments; Flocculation; Multimodal; Particle sizedistribution; Population balance equations |
| Authors | | Top | - Lee, B.J.
- Toorman, E., more
- Fettweis, M., more
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| Abstract | Multimodal particle size distributions (PSDs) of fine-grained cohesive sediments are common in marine and coastal environments. The curve-fitting software in this study decomposed such multimodal PSDs into subordinate log-normal PSDs. Four modal peaks, consisting of four-level ordered structures of primary particles, flocculi, microflocs, and macroflocs, were identified and found to alternately rise and sink in a flow-varying tidal cycle due to shear-dependent flocculation. The four modal PSD could be simplified further into two discrete size groups of flocculi and flocs. This allowed the development of a two-class population balance equation (TCPBE) model with flocculi and flocs to simulate flocculation involving multimodal PSDs. The one-dimensional vertical (1-DV) TCPBE model further incorporated the Navier-Stokes equation with the k-epsilon turbulence closure and the sediment mass balance equations. Multimodal flocculation as well as turbulent flow and sediment transport in a flow-varying tidal cycle could be simulated well using the proposed model. The 1-DV TCPBE was concluded to be the simplest model that is capable of simulating multimodal flocculation in the turbulent flow field of marine and coastal zones. |
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