Recently, two wave models based on the stream-function theory have been derived from Hamilton’s principle for gravity waves. One is the irrotational Green–Naghdi (IGN) equation and the other is the complementary mild-slope equation (CMSE). The IGN equation has been derived to describe refraction and diffraction of nonlinear gravity waves in the time domain and in water of finite but arbitrary bathymetry. The CMSE has been derived to consider the same problem in the (linear) frequency domain. In this paper, we first discuss the two models from the viewpoint of Hamilton’s principle. Then the two models are applied to a resonant scattering of Stokes waves over periodic undulations, or the Bragg scattering problem. The numerical results are compared with existing numerical predictions and experimental data. It is found here that Level 3 IGN equation can describe Bragg scattering well for arbitrary bathymetry.

1.
Wu
,
T. Y.
, 1999, “
Modelling Nonlinear Dispersive Water Waves
,”
J. Eng. Mech.
0733-9399,
125
, pp.
747
755
.
2.
Kennedy
,
A. B.
,
Kirby
,
J. T.
,
Chen
,
Q.
, and
Dalrymple
,
R. A.
, 2001, “
Boussinesq-Type Equations With Improved Nonlinear Performance
,”
Wave Motion
0165-2125,
33
(
3
), pp.
225
243
.
3.
Madsen
,
P. A.
,
Bingham
,
H. B.
, and
Schäffer
,
H. A.
, 2003, “
Boussinesq-Type Formulations for Fully Nonlinear and Extremely Dispersive Water Waves: Derivation and Analysis
,”
Proc. R. Soc. London, Ser. A
0950-1207,
459
, pp.
1075
1104
.
4.
Fuhrman
,
D. R.
, and
Bingham
,
H. B.
, 2004, “
Numerical Solutions of Fully Non-Linear and Highly Dispersive Boussinesq Equations in Two Horizontal Dimensions
,”
Int. J. Numer. Methods Fluids
0271-2091,
44
, pp.
231
255
.
5.
Berkhoff
,
J. C. W.
, 1973, “
Computation of Combined Refraction-Diffraction
,”
Proceedings of the 13th International Conference on Coastal Engineering
,
ASCE
,
Vancouver, Canada
, pp.
471
490
.
6.
Chamberlain
,
P. G.
, and
Porter
,
D.
, 1995, “
The Modified Mild-Slope Equation
,”
J. Fluid Mech.
0022-1120,
291
, pp.
393
407
.
7.
Massel
,
S. R.
, 1993, “
Extended Reflection-Diffraction Equation for Surface Waves
,”
Coastal Eng.
0378-3839,
19
, pp.
97
126
.
8.
Porter
,
D.
, and
Staziker
,
D. J.
, 1995, “
Extensions of the Mild-Slope Equation
,”
J. Fluid Mech.
0022-1120,
300
, pp.
367
382
.
9.
Chandrasekera
,
C. N.
, and
Cheung
,
K. F.
, 2001, “
Linear Refraction-Diffraction Model for Steep Bathymetry
,”
J. Waterway, Port, Coastal, Ocean Eng.
0733-950X,
127
, pp.
161
170
.
10.
Madsen
,
P. A.
,
Fuhrman
,
D. R.
, and
Wang
,
B.
, 2006, “
A Boussinesq-Type Method for Fully Nonlinear Waves Interacting With a Rapidly Varying Bathymetry
,”
Coastal Eng.
0378-3839,
53
, pp.
487
504
.
11.
Kim
,
J. W.
,
Bai
,
K. J.
,
Ertekin
,
R. C.
, and
Webster
,
W. C.
, 2001, “
A Derivation of the Green–Naghdi Equations for Irrotational Flows
,”
J. Eng. Math.
0022-0833,
40
(
1
), pp.
17
34
.
12.
Kim
,
J. W.
,
Bai
,
K. J.
,
Ertekin
,
R. C.
, and
Webster
,
W. C.
, 2003, “
A Strongly-Nonlinear Model for Water Waves in Water of Variable Depth—The Irrotational Green–Naghdi Model
,”
ASME J. Offshore Mech. Arct. Eng.
0892-7219,
125
(
1
), pp.
25
32
.
13.
Kim
,
J. W.
, and
Ertekin
,
R. C.
, 2000, “
A Numerical Study of Nonlinear Wave Interaction in Irregular Seas: Irrotational Green–Naghdi Model
,”
Marine Struct.
,
13
(
4–5
), pp.
331
347
.
14.
Kim
,
J. W.
, and
Bai
,
K. J.
, 2004, “
A New Complementary Mild-Slope Equation
,”
J. Fluid Mech.
0022-1120,
511
, pp.
25
40
.
15.
Dean
,
R. G.
, 1965, “
Stream Function Representation of Nonlinear Ocean Waves
,”
J. Geophys. Res.
0148-0227,
70
, pp.
4561
4572
.
16.
Bai
,
K. J.
, 1977, “
Sway Added-Mass of Cylinders in a Canal Using Dual-Extremum Principles
,”
J. Ship Res.
0022-4502,
21
(
4
), pp.
193
199
.
17.
Bai
,
K. J.
, and
Han
,
J. H.
, 1994, “
A Localized Finite-Element Method for the Nonlinear Steady Waves Due to a Two-Dimensional Hydrofoil
,”
J. Ship Res.
0022-4502,
38
(
1
), pp.
42
51
.
18.
Green
,
A. E.
,
Laws
,
N.
, and
Naghdi
,
P. M.
, 1974, “
On the Theory of Water Waves
,”
Proc. R. Soc. London, Ser. A
0950-1207,
338
, pp.
43
55
.
19.
Ertekin
,
R. C.
,
Webster
,
W. C.
, and
Wehausen
,
J. V.
, 1986, “
Waves Caused by a Moving Disturbance in a Shallow Channel of Finite Width
,”
J. Fluid Mech.
0022-1120,
169
, pp.
275
292
.
20.
Shields
,
J. J.
, and
Webster
,
W. C.
, 1988, “
On Direct Methods in Water-Wave Theory
,”
J. Fluid Mech.
0022-1120,
197
, pp.
171
199
.
21.
Xu
,
Q.
,
Pawlowski
,
J. W.
, and
Baddour
,
R. E.
, 1997, “
Development of Green–Naghdi Models With a Wave-Absorbing Beach for Nonlinear, Irregular Wave Propagation
,”
J. Mar. Sci. Technol.
0948-4280,
2
(
1
), pp.
21
34
.
22.
Davies
,
A. G.
, and
Heathershaw
,
A. D.
, 1984, “
Surface-Wave Propagation Over Sinusoidally Varying Topography
,”
J. Fluid Mech.
0022-1120,
144
, pp.
419
443
.
23.
Mei
,
C. C.
, 1985, “
Resonant Reflection of Surface Water Waves by Periodic Sandbars
,”
J. Fluid Mech.
0022-1120,
152
, pp.
315
335
.
24.
Kirby
,
J. T.
, 1986, “
A General Wave Equation for Waves Over Tippled Beds
,”
J. Fluid Mech.
0022-1120,
162
, pp.
171
186
.
25.
Guazzelli
,
E.
,
Rey
,
V.
, and
Belzons
,
M.
, 1992, “
Higher-Order Bragg Reflection of Gravity Surface Waves by Periodic Beds
,”
J. Fluid Mech.
0022-1120,
245
, pp.
301
317
.
26.
Miles
,
J. W.
, and
Chamberlain
,
P. G.
, 1998, “
Topographical Scattering of Gravity Waves
,”
J. Fluid Mech.
0022-1120,
361
, pp.
175
188
.
27.
Porter
,
R.
, and
Porter
,
D.
, 2003, “
Scattered and Free Waves Over Periodic Beds
,”
J. Fluid Mech.
0022-1120,
483
, pp.
129
163
.
28.
Liu
,
Y.
, and
Yue
,
D. K. P.
, 1998, “
On Generalized Bragg Scattering of Surface Waves by Bottom Ripples
,”
J. Fluid Mech.
0022-1120,
356
, pp.
297
326
.
29.
Goldstein
,
H.
, 1980,
Classical Dynamics
, 2nd ed.,
Addison-Wesley
,
Reading, MA
.
30.
Bai
,
K. J.
, and
Yeung
,
R. W.
, 1974, “
Numerical Solutions of Free Surface Flow Problem
,”
Proceedings of the Tenth Symposium on Naval Hydrodynamics
,
Office of Naval Research
,
Cambridge, MA
, pp.
609
641
.
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