6.3 Bottom and a Non-Uniform Current Influence on Waves
279
z
Direction
of initial wave
propagation
z
a)
b)
~ H
/
Fig. 6.11. Wave propagation in fair increasing (a) and decreasing (b) currents
the corresponding relative calculated values of the mean wave elements h, 5., 7
as functions of the parameter "(, characterizing relative variations of current
velocity (or depth), are presented schematically in Figs. 6.11~6.15. The value
"( = 1 corresponds to wave elements at the initial boundary. The value "( > 1
describes wave variations taking place with the wave propagating in the area
with increasing current velocity (or decreasing depth). The value "( < 1 describes the situation of wave propagation in a decreasing current. The use of
a logarithmic scale presents the results in a more compact form.
Wave propagation in a deep water fair current (see Fig. 6.11) will be considered in detail (i.e. when the effect of depth variations is of no importance).
However, unlike the second test results, the initial current velocity will be
considered to be significantly different from zero, assuming that v = 0.1.
Wave element variations in this case are shown in Fig. 6.12a.
The wave heights are monotonically decreased, and their lengths are increased in the fair increasing current ( "( > 1). The wave periods are constant
and later on they are decreased at "( > 6.0. In a fair decreasing current
('I< 1), the wave periods are practically constant, the heights are increased
and the lengths are decreased. The wave parameter variations become more
intensive with increasing initial current velocity.
279
z
Direction
of initial wave
propagation
z
a)
b)
~ H
/
Fig. 6.11. Wave propagation in fair increasing (a) and decreasing (b) currents
the corresponding relative calculated values of the mean wave elements h, 5., 7
as functions of the parameter "(, characterizing relative variations of current
velocity (or depth), are presented schematically in Figs. 6.11~6.15. The value
"( = 1 corresponds to wave elements at the initial boundary. The value "( > 1
describes wave variations taking place with the wave propagating in the area
with increasing current velocity (or decreasing depth). The value "( < 1 describes the situation of wave propagation in a decreasing current. The use of
a logarithmic scale presents the results in a more compact form.
Wave propagation in a deep water fair current (see Fig. 6.11) will be considered in detail (i.e. when the effect of depth variations is of no importance).
However, unlike the second test results, the initial current velocity will be
considered to be significantly different from zero, assuming that v = 0.1.
Wave element variations in this case are shown in Fig. 6.12a.
The wave heights are monotonically decreased, and their lengths are increased in the fair increasing current ( "( > 1). The wave periods are constant
and later on they are decreased at "( > 6.0. In a fair decreasing current
('I< 1), the wave periods are practically constant, the heights are increased
and the lengths are decreased. The wave parameter variations become more
intensive with increasing initial current velocity.