Table 2. Typical values for shear stresses, Pa

ERDC TN-DOER-E10

April 2000

b. For the other size classes, SSFATE uses

Pi = 0, if τ ≥ τuli

(18)

Pi = 1.0, if τ ≤ τlli

(19)

where

τuli

= the shear stress above which no deposition occurs for grain class i

τlli

= the shear stress below which the deposition probability for grain class i is 1.0

For values of τ between τlli and τuli , linear interpolation is used.

Typical values for τRR, and τuR are given in

Table 2

Table 2.

Typical values for shear stresses, Pa

τlli

τuli

Class

A typical value for τcd is 0.016 Pa.

0.016

0.03

0.06

Next, the deposition of sediment from each size

0.06

0.20

class from each bottom cell during the current

0.20

0.90

time-step is computed. The computations start

with the largest size class:

Fluxi = bi Ci Wsi Pi

(20)

where bi is a probability parameter that includes all other factors influencing deposition other than

shear.

This mass is then removed from the particles occupying the cell. The deposition for the remaining

size classes is then computed, starting with the second largest size class and working down to the

smallest. This deposition is computed as follows:

If 0 ≤ Pi ≤ 0.05, then

C Fluxi +1

Fluxi = i

(21)

Ci +1 + 1

otherwise,

Fluxi = bi Ci Wsi Pi

(22)