2. Characteristics and Motion of Sédiments
35
Shields
Parameter
Fig. 2.5 Shields parameter as function of dimensionless parameter.
and bind the sédiment together into a mass that is very résistant to
érosion.
• The Shields parameter for gravel is constant at 0.06, implying that Shields
stress here becomes a simple function of grain size.
Problem I
Quartz sédiment in seawater with a médian sédiment dia P50 = 0.15 mm.
Find,
(a) With wave period T — 10 s, the minimum wave height for sand motion
in water depth d = 10 m.
(b) With wave period T = 8 s, the maximum water depth for sand motion
with H = 2 ni.
(c) with H — 1 m, d = 20 m the minimum wave period for sand motion
D$q — 0.15 mm = 0.00015 m.
Solution
\
10-5
— — 1 ) gD50
7
/
J
^max(—d) — 8
8 (
_ 1 ) 9.8I x 0.00015
\ 1.026
J
0.5
= 0.1365 m/s
35
Shields
Parameter
Fig. 2.5 Shields parameter as function of dimensionless parameter.
and bind the sédiment together into a mass that is very résistant to
érosion.
• The Shields parameter for gravel is constant at 0.06, implying that Shields
stress here becomes a simple function of grain size.
Problem I
Quartz sédiment in seawater with a médian sédiment dia P50 = 0.15 mm.
Find,
(a) With wave period T — 10 s, the minimum wave height for sand motion
in water depth d = 10 m.
(b) With wave period T = 8 s, the maximum water depth for sand motion
with H = 2 ni.
(c) with H — 1 m, d = 20 m the minimum wave period for sand motion
D$q — 0.15 mm = 0.00015 m.
Solution
\
10-5
— — 1 ) gD50
7
/
J
^max(—d) — 8
8 (
_ 1 ) 9.8I x 0.00015
\ 1.026
J
0.5
= 0.1365 m/s