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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Hydro-environment : Non-fickian modeling of pollutant mixing during initial period in open channels
Non-fickian modeling of pollutant mixing during initial period in open channels
Author : IL WON SEO (1) & INHWAN PARK(2)
ABSTRACT
A non-Fickian dispersion model, 2D Particle Dispersion Model (PDM-2D), which can be applicable in both the initial and
Taylor periods was developed using the simple arithmetic algorithm. In PDM-2D, mixing process of a soluble pollutant was
represented by the motion of the neutrally buoyant pollutant particles, and the process was divided into two stages, the
shear advection stage and the vertical diffusion stage. In the shear advection stage, neutrally buoyant pollutant particles
were translated in longitudinal and transverse directions following velocity formulas, and then the separated particles were
distributed into vertical layers during each time step in the vertical diffusion stage. Then, at the end of each time step,
result is the scattering of pollutant particles in the longitudinal and transverse directions. PDM-2D was applied to the open
channel flows, and the simulation results were compared with the Fickian dispersion model. Concentration curves from
this study showed a skewed distribution in the initial period, and then turned into the symmetric Gaussian distribution in
the Taylor period where the balance between shear advection and vertical diffusion was achieved. The skewness
coefficient was rapidly decreased in the transition period. From the simulated concentration distributions, dispersion
coefficients were calculated using the routing method. In the advection-dominant mixing region, the non-dimensional
longitudinal dispersion coefficient were closed to 5.93, which was suggested by Elder (1959) in the diffusion-dominant
mixing region. The simulation results in the meandering channel shows that the breakthrough curves were well fitted with
the experimental results on the apex region.
File Size : 508,459 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Hydro-environment
Date Published : 28/08/2015
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