poster - International Conference of Agricultural Engineering

ps (cm·s)
Water depth (m)
Water depth (m)
Water depth (m)
Water depth (m)
coverage. On the other hand, the power spectra shift greatly from Eq.1 in the case of Type A.
This indicates that the development of water surface wave is significantly inhibited by the
existence of the coverage in Type A. Moreover, the power spectra in the case of Type B and
Type C demonstrate the wind is developed enough compared with Type A. This means that
the development of the wind wave was not greatly intercepted because the progressive wave
passed through the area where the coverage did not exist. These experimental results also
indicate that the layout of floating object with respect to the wind direction significantly affects
on the hydraulic structure in the waters.
1.E-02
1.E-02
1.E-02
1.E-02
1.E-03
1.E-03
1.E-03
1.E-03
1.E-04
1.E-04
1.E-04
1.E-04
1.E-05
1.E-05
1.E-05
1.E-05
1.E-06
1.E-06
1.E-06
1.E-06
1.E-07
1.E-07
1.E-07
1.E-07
1.E-08
1.E-08
1.E-08
1.E-08
1 10 100 1 10 100 1 10 100 1 10 100
f (Hz)
f (Hz)
f (Hz)
f (Hz)
(a) No coverage (b) Type A (c) Type B (d) Type C
FIGURE 2: Experimental equipment
To investigate the effect of floating object existence in detail, the characteristics of the flow
velocity and the turbulent energy in the cases of Type A and no coverage are compared in
Fig. 3. In the case of no coverage, the flow velocity decreases from the water surface to
about 1/3 of depth (wind-induced current), and the flow reverses in deeper layer (return
current). That is, it turns out that the vertical circulation flow arises in the test tank. The
turbulent energy is largest near the water surface. On the other hand, in the case of Type A,
the flow velocity under the coverage is very small and two wind-induced circulations are
formed at both the upwind and downwind portions of the coverage. The distribution of the
turbulent energy is also small in the downwind portion of coverage.
3. Numerical simulation
3.1 Material and Methods
8cm/s
0
10
20
30
40 0 100 200 300 400 500 600
(a) Flow velocity (No coverage)
0.5cm 2 /s 2
0
10
20
30
40 0 100 200 300 400 500 600
(b) Turbulent energy (No coverage)
8cm/s
0
10
20
30
40 0 100 200 300 400 500 600
(c) Flow velocity (Type A)
0.5cm 2 /s 2
0
10
20
30
40 0 100 200 300 400 500 600
(d) Turbulent energy (Type A)
FIGURE 3: Experimental equipment