On the use of random walk models with spatially variable diffusivity
Hunter, JA and Craig, PD and Phillips, HE (1993) On the use of random walk models with spatially variable diffusivity. Journal of Computational Physics, 106 (2). pp. 366376. ISSN 00219991  PDF  Full text restricted  Requires a PDF viewer 1059Kb  
Official URL: http://dx.doi.org/10.1016/S00219991(83)711149 AbstractThe random walk technique is commonly used to model diffusion in
the environment. For a constant diffusivity K and model timestep dt.
the random step should be chosen from a distribution with variance
2Kdt. However, if K varies spatially, this choice of step leads to the
accumulation of particles in regions of low diffusivity. This problem
may be overcome either by the incorporation of an apparent advection
velocity, or by transforming to a coordinate system in which the
diffusivity is constant. The latter technique requires no immediate
approximations, is applicable to any reasonable diffusivity field and is
therefore the preferred approach. In this case, as with constant K, the
random step should be chosen from a normal distribution, for reasons
of both theoretical accuracy and computational efficiency. Three
important aspects of model design are discussed: the selection of the
random number generator, the time step and the total number of
particles. Item Type:  Article 

Additional Information:  http://www.elsevier.com/wps/find/homepage.cws_home 

Keywords:  diffusivity
eddy
random walk 

ID Code:  815 

Deposited By:  Dr Helen E Phillips 

Deposited On:  07 Mar 2007 

Last Modified:  18 Jul 2008 19:49 

ePrint Statistics:  View statistics for this ePrint 

Repository Staff Only: item control page
