The dispersion describes the transport due to molecular diffusion and due to non-resolved turbulence or eddies. In coastal areas the dispersion due to non-resolved turbulence is normally by far the most important. In the horizontal directions the effects of non-resolved turbulence can be significant, in which case the dispersion coefficient should depend on the resolution.
In coastal areas it is important to distinguish between horizontal dispersion due to e.g. non-resolved eddies, and vertical dispersion due to e.g. bed generated turbulence. Hence, dispersion in horizontal and vertical directions is specified separately. Individual particles cannot break into pieces and therefore the process of dispersion is implemented as a likelihood to move in a random direction.
The dispersion is specified individually for each particle class.
Dispersion specification
Recommended values