TY - JOUR
T1 - Dynamics of freshwater-seawater mixing zone development in dual-domain formations
AU - Lu, Chunhui
AU - Luo, Jian
PY - 2010
Y1 - 2010
N2 - Dynamic responses of freshwater-seawater mixing zones to seasonal freshwater-level fluctuations and the presence of kinetic mass transfer between mobile and immobile domains have been analyzed using numerical models. Mixing enhancement is mainly controlled by the unsynchronized behavior of concentration distributions in the mobile and immobile domain. Such effect is maximized at the aquifer bottom when the retention timescale (the reciprocal of mass transfer rate) in the immobile domain is comparable to the period of freshwater-level fluctuations. Kinetic mass transfer may alter the time lag between periodic freshwater-level fluctuations and the movement of the mixing zone, causing the expansion and contraction of the mixing zone. Mixing enhancement by kinetic mass transfer is nonuniform in the mixing zone, and the mixing zone thickness may vary significantly within a period. By contrast, large dispersion coefficients may create thicker mixing zones but may not cause such unsynchronized behavior and alter the time lags of different concentration contour lines; that is, the mixing enhancement is rather uniform in the mixing zone. The dynamics of mixing zone development is sensitive to the flow velocity, which is influenced by the hydraulic conductivity, amplitude of the freshwater-level fluctuations, and the capacity ratio of kinetic mass transfer.
AB - Dynamic responses of freshwater-seawater mixing zones to seasonal freshwater-level fluctuations and the presence of kinetic mass transfer between mobile and immobile domains have been analyzed using numerical models. Mixing enhancement is mainly controlled by the unsynchronized behavior of concentration distributions in the mobile and immobile domain. Such effect is maximized at the aquifer bottom when the retention timescale (the reciprocal of mass transfer rate) in the immobile domain is comparable to the period of freshwater-level fluctuations. Kinetic mass transfer may alter the time lag between periodic freshwater-level fluctuations and the movement of the mixing zone, causing the expansion and contraction of the mixing zone. Mixing enhancement by kinetic mass transfer is nonuniform in the mixing zone, and the mixing zone thickness may vary significantly within a period. By contrast, large dispersion coefficients may create thicker mixing zones but may not cause such unsynchronized behavior and alter the time lags of different concentration contour lines; that is, the mixing enhancement is rather uniform in the mixing zone. The dynamics of mixing zone development is sensitive to the flow velocity, which is influenced by the hydraulic conductivity, amplitude of the freshwater-level fluctuations, and the capacity ratio of kinetic mass transfer.
UR - http://www.scopus.com/inward/record.url?scp=78649494694&partnerID=8YFLogxK
U2 - 10.1029/2010WR009344
DO - 10.1029/2010WR009344
M3 - Article
VL - 46
JO - Water Resources Research
JF - Water Resources Research
SN - 0043-1397
IS - 11
M1 - W11601
ER -