FN Archimer Export Format
PT J
TI On the behavior of mud floc size distribution: model calibration and model behavior
BT 
AF MIETTA, Francesca
   CHASSAGNE, Claire
   VERNEY, Romaric
   WINTERWERP, Johan C.
AS 1:1;2:1;3:2;4:1,3;
FF 1:;2:;3:PDG-ODE-DYNECO-PHYSED;4:;
C1 Delft Univ Technol, Fac Civil Engn & Geosci, NL-2600 GA Delft, Netherlands.
   IFREMER, Lab Dyneco Physed, F-29280 Plouzane, France.
   Deltares, NL-2600 MH Delft, Netherlands.
C2 UNIV DELFT, NETHERLANDS
   IFREMER, FRANCE
   DELTARES, NETHERLANDS
SI BREST
SE PDG-ODE-DYNECO-PHYSED
IN WOS Ifremer jusqu'en 2018
   copubli-europe
IF 1.774
TC 27
UR https://archimer.ifremer.fr/doc/00028/13875/11033.pdf
LA English
DT Article
DE ;Flocculation;Population balance equation;Discretization into classes;Kaolinite;Natural mud;zeta-Potential
AB In this paper, we study a population balance equation (PBE) where flocs are distributed into classes according to their mass. Each class i contains i primary particles with mass m p and size L p. All differently sized flocs can aggregate, binary breakup into two equally sized flocs is used, and the floc’s fractal dimension is d 0 = 2, independently of their size. The collision efficiency is kept constant, and the collision frequency derived by Saffman and Turner (J Fluid Mech 1:16–30, 1956) is used. For the breakup rate, the formulation by Winterwerp (J Hydraul Eng Res 36(3):309–326, 1998), which accounts for the porosity of flocs, is used. We show that the mean floc size computed with the PBE varies with the shear rate as the Kolmogorov microscale, as observed both in laboratory and in situ. Moreover, the equilibrium mean floc size varies linearly with a global parameter P which is proportional to the ratio between the rates of aggregation and breakup. The ratio between the parameters of aggregation and breakup can therefore be estimated analytically from the observed equilibrium floc size. The parameter for aggregation can be calibrated from the temporal evolution of the mean floc size. We calibrate the PBE model using mixing jar flocculation experiments, see Mietta et al. (J Colloid Interface Sci 336(1):134–141, 2009a, Ocean Dyn 59:751–763, 2009b) for details. We show that this model can reproduce the experimental data fairly accurately. The collision efficiency α and the ratio between parameters for aggregation and breakup α and E are shown to decrease linearly with increasing absolute value of the ζ-potential, both for mud and kaolinite suspensions. Suspensions at high pH and different dissolved salt type and concentration have been used. We show that the temporal evolution of the floc size distribution computed with this PBE is very similar to that computed with the PBE developed by Verney et al. (Cont Shelf Res, 2010) where classes are distributed following a geometrical series and mass conservation is statistically ensured. The same terms for aggregation and breakup are used in the two PBEs. Moreover, we argue, using both PBEs, that bimodal distributions become monomodal in a closed system with homogeneous sediment, even when a variable shear rate is applied.
PY 2011
PD MAR
SO Ocean Dynamics
SN 1616-7341
PU Springer Heidelberg
VL 61
IS 2-3
UT 000289528200009
BP 257
EP 271
DI 10.1007/s10236-010-0330-2
ID 13875
ER

EF