92
Coastal Engineering: Theory and Practice
where, X = 50 m , W = width of surf zone
/ 50
Wr/0,2 \204.36
u / Lri
x
t < 50
~ 0-714 (204.36 In
= 0.2949
204.36 /
Pls =
pgHsbWVLEoCf
5?r
2
Vo LH
1024 x 9.81 x 1.9925 x 204.36 x -0.32 x 0.01
x 0.2949
= -5652 N/s
Q = (1290/12) x -5652 = -607624 m3/month
Similarly for other months the calculations are tabulated below
Month
Hsb
(m)
W (m)
Vleo
(m/s)
(V/V0)lw
Pia(N/s)
Q (m3/month)
J an
1.99
204.37 -0.32
0.2949
-5652
-607624.8
Feb
2.17
222.15 -0.31
0.2847
-6702
-720457.1
Mar
1.99
204.37 -0.28
0.2949
-4946
-531671.7
Apr
1.52
155.96 -0.09
0.3245
-841.3
-90434.93
May
1.72
176.12 -0.14
0.312
-1736
-186577.8
June
3.00
308.19
0.4
0.2431
19487
2094893
July
3.24
332.37
0.35
0.2335
20646
2219458
Aug
2.59
265.59
0.19
0.2621
6376.1
685430.4
Sep
2.59
265.59
0.22
0.2621
7382.8
793656.3
Oct
1.84
188.93 -0.38
0.3041
-5562
-597931.4
Nov
1.31
134.4
-0.12
0.3371
-802
-86218.21
Dec
1.59
162.82 -0.18
0.3203
-1858
-199728.2
Direction of drift
m3/yr
Southernly drift
-3020644
Northernly drift
5793437
Gross drift
8814081
Net drift (towards North)
2772793