en
en
Velocity 1 1
(ft/se c)
Limiting or Minimum Velocity for the Initiation of Motion of Sand of a Given Size.
Limiting velocity, arbitrarily defined as equal to 7u*„ where u# is the threshold or critical friction
velocity. (Inman, 1949.) For unidirectional flow this relation would give a limiting velocity équivalent, for
example, to the mean velocity measured 1 foot above a bottom which has a roughness length of 2 cm.
Field observations near the surf zone indicate that planation and disappearance of ripples does not occur
unless the maximum velocity associated with the wave crest somewhat exceeds that listed by Ménard and
Manohar.
Figure 4-22.
Initiation of Ripple Motion
en
Velocity 1 1
(ft/se c)
Limiting or Minimum Velocity for the Initiation of Motion of Sand of a Given Size.
Limiting velocity, arbitrarily defined as equal to 7u*„ where u# is the threshold or critical friction
velocity. (Inman, 1949.) For unidirectional flow this relation would give a limiting velocity équivalent, for
example, to the mean velocity measured 1 foot above a bottom which has a roughness length of 2 cm.
Field observations near the surf zone indicate that planation and disappearance of ripples does not occur
unless the maximum velocity associated with the wave crest somewhat exceeds that listed by Ménard and
Manohar.
Figure 4-22.
Initiation of Ripple Motion