User:Jiamingshi/sandbox

Shear velocity also helps in thinking about the rate of shear and dispersion in a flow. Shear velocity scales well to rates of dispersion and bedload sediment transport. A general rule is that the shear velocity is between 5% to 10% of the mean flow velocity.

For river base case, the shear velocity can be calculated by Manning's equation.

u*= *(n/a)*(g*Rh^(-1/3))^0.5 Instead of finding n and Rh for your specific river of interest, you can examine the range of possible values and note that for most rivers, u* is between 5% and 10% of :
 * n is the Gauckler–Manning coefficient. Units for values of n are often left off, however it is not dimensionless, having units of: (T/[L1/3]; s/[ft1/3]; s/[m1/3]).
 * Rh is the hydraulic radius (L; ft, m);
 * the role of a is a dimension correct factor. Thus a= 1 m^(1/3)/s = 1.49 ft^(1/3)/s.

reflection and absorption of a contaminant plume off of an impenetrable (no-flux) boundary.

The absorption process will be just the opposite of reflection. We should add an Mirror symmetry image as an addition sink, and substract the part of the concentration that has been absorbed.