Geoscience Reference
In-Depth Information
Van Niekerk
et al
. (1992) related the mixing layer thickness to the dimensionless
bed shear stress as follows:
2
d
50
τ
b
τ
δ
=
(2.165)
m
c
50
τ
b
is the skin friction
where
d
50
is the median size of bed material in the mixing layer,
component of bed shear stress, and
τ
c
50
is the critical shear stress for incipient motion
corresponding to
d
50
.
Wu and Vieira (2002) set the mixing layer thickness as the larger of half the sand
dune height and twice the sediment size:
δ
=
max
[
0.5
,2
d
50
]
(2.166)
m
where
is the sand dune height, which can be calculated using the van Rijn (1984c)
formula.
The mixing layer thickness is an important parameter in non-uniform sediment
transport models. The sensitivity of model results to it is demonstrated in Section 5.6.
