TY  - JOUR
AU  - Suciu, N.
AU  - Vamos, C.
AU  - Radu, F.A.
AU  - Vereecken, H.
AU  - Knabner, P.
TI  - Persistent memory of diffusing particles
JO  - Physical review / E
VL  - 80
IS  - 6
SN  - 1539-3755
CY  - College Park, Md.
PB  - APS
M1  - PreJuSER-7819
SP  - 061134
PY  - 2009
N1  - Record converted from VDB: 12.11.2012
AB  - The variance of the advection-diffusion processes with variable coefficients is exactly decomposed as a sum of dispersion terms and memory terms consisting of correlations between velocity and initial positions. For random initial conditions, the memory terms quantify the departure of the preasymptotic variance from the time-linear diffusive behavior. For deterministic initial conditions, the memory terms account for the memory of the initial positions of the diffusing particles. Numerical simulations based on a global random walk algorithm show that the influence of the initial distribution of the cloud of particles is felt over hundreds of dimensionless times. In case of diffusion in random velocity fields with finite correlation range the particles forget the initial positions in the long-time limit and the variance is self-averaging, with clear tendency toward normal diffusion.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000273227500045
DO  - DOI:10.1103/PhysRevE.80.061134
UR  - https://juser.fz-juelich.de/record/7819
ER  -