Random walk simulation has the potential to be an extremely powerful tool in the ~nvestigation of turbulence in environmental processes. However, care must be taken in applylng such simulat~ons to the mohon of particles in turbulent marine systems where turbulent diffusivity IS conlmonly spatially non-uniform. The problems associated with this nonuniformity are far from negligible and have been...

Direct numerical simulations and mean-field theory are used to model reactive front propagation in a turbulent medium. In the mean-field approach, memory effects of turbulent diffusion are taken into account to estimate the front speed in cases in which the Damköhler number is large. This effect is found to saturate the front speed to values comparable with the speed of the turbulent motions. B...